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CHAPTER 7: MAINTENANCE

MODEL 250DP DUAL PULSE

RESISTANCE WELDING POWER SUPPLY

7-2

990-280

Figure 7-1. Line Voltage and Capacitor Bank Jumpering

1. Display units should be set to % Energy not Watt-Seconds.

2. Set the front panel POWER switch to OFF.

3. Remove the cover.

4. Remove Jumper A connecting the center terminals.

5. Remove Jumper B connecting the positive terminals.

6. Replace

the

cover.

Line Voltage Changes

You may reconnect the power supply to operate at different line voltages: 100, 115, 208 or 230 VAC,
50/60 Hz. To reconfigure the line power input circuitry, proceed as follows:

1. Set the front panel POWER switch to OFF.

Summary of Contents for 250DP

Page 1: ...ELDING POWER SUPPLIES Model Stock No 250DP 1 250 XX 250DP 208 1 250 XX 01 250DP 230 1 250 XX 02 250DP 100 1 250 XX 03 250DPS 1 254 XX 250DPS 208 1 254 XX 01 250DPS 230 1 254 XX 02 250DPS 100 1 254 XX 03 NOTE Units with the built in Weld Sentry Option also require User s Manual No 990 291 ...

Page 2: ...f America Revision Record Revision EO Date Basis of Revision A ENRG RLSE 1 94 Released Original Manual B 17215 11 97 Ɣ Reorganize data and update format Ɣ Incorporate Addendum 995 280 Rev A 10 97 and Errata 996 280 Rev B C 17405 4 98 Add operating features D 17574 6 98 Correct Test Point designation E 18282 5 00 Ɣ Add CAUTION statement about polarity in chained weld schedules Ɣ Add Declaration of ...

Page 3: ... 2 3 Firing Switch Connections 2 4 Mechanical Firing Switch 2 4 Optical Firing Switch 2 4 3 Wire Firing Switches 2 4 Air Actuated Weld Head Connections 2 5 Air Valve Driver 2 6 Non Miyachi Unitek Air Actuated Weld Heads 2 7 Air Actuated Weld Heads without Force Firing Switches 2 7 Second Air Head 2 7 Footswitch 2 7 1 Level Footswitch 2 7 2 Level Footswitch 2 8 Remote Schedule Selection 2 8 Relay O...

Page 4: ...ld 5 4 Weak Weld 5 5 Electrode Sticking 5 5 Causes of Imperfect Welds 5 5 Electrode Force and Energy 5 5 Polarity 5 6 Weld Strength Profiles 5 7 Destructive Testing 5 7 Electrode Maintenance 5 8 CHAPTER 6 PROCESS DEFINITIONS AND WELD FUNCTIONS 6 1 250DP States 6 1 RUN State 6 1 STANDBY State 6 2 PROGRAM State 6 2 MENU State 6 3 HELP State 6 4 NO WELD State 6 4 FIRE State 6 4 Weld Function Field 6 ...

Page 5: ... A 2 Line Failure Turndown A 2 Over Voltage Lockout A 3 Charge Lockout Circuit A 3 Polarity Selection A 3 Welding Speed A 3 Weld Schedules A 6 Weld Schedule Definition A 6 Options A 6 Schedule Number at Power Up A 7 Utilities A 7 Information A 7 Weld Sentry A 7 System Set up A 8 Weld Functions A 8 Head Type A 8 Squeeze Line A 8 Cool Time A 9 Hold Time A 9 Footswitch Type A 9 FOOTSWITCH Connector A...

Page 6: ...ir Valve Driver A 14 Air Valve Driver 1 A 14 Air Valve Driver 2 A 15 Air Valve Driver Receptacles A 15 Control Signals Connector A 15 Emergency Stop A 16 Charge Process Inhibit A 17 Remote Weld Schedule Selection A 17 Binary Schedule Selection Code A 18 Relay Outputs A 19 Accessory Port A 20 Input Output Cable Connectors and Fusing A 20 Input Line Power A 20 Circuit Breakers A 20 Fuses A 20 Power ...

Page 7: ... of the Weld Head with a Force Gauge 4 4 4 4 Results of Excessive Air Pressure 4 5 4 5 Weld Head Configuration Jumper Selection 4 6 5 1 Effects of Excessive or Insufficient Heat Time and Pressure 5 2 5 2 Typical Weld Strength Profile 5 7 7 1 Line Voltage and Capacitor Bank Jumpering 7 2 7 2 100 VAC Line Voltage Configuration 7 4 7 3 115 VAC Line Voltage Configuration 7 5 7 4 208 VAC Line Voltage C...

Page 8: ...e Title Page 5 1 Recommended Electrode Materials 5 3 5 2 Causes of Imperfect Welds 5 5 7 1 Power Supply Voltage Range Specifications 7 9 A 1 Pulse Characteristics A 2 A 2 Welding Speed A 4 A 3 Binary Codes for Remote Weld Schedule Selection A 17 A 4 Input Power Specifications A 21 ...

Page 9: ...ue P O Box 5033 Monrovia CA 91017 7133 Telephone 626 303 5676 FAX 626 358 8048 e mail info miyachiunitek com The purpose of this manual is to supply operating and maintenance personnel with the information needed to properly and safely operate and maintain the Model 250DP Dual Pulse Resistance Welding Power Supply We have made every effort to ensure that the information in this manual is accurate ...

Page 10: ...ng to use the workstation Procedures other than those described in this manual or not performed as prescribed in it may expose personnel to electrical hazards After reading this manual retain it for future reference when any questions arise regarding the proper and SAFE operation of the tester Please note the following conventions used in this manual WARNING Comments marked this way warn the reade...

Page 11: ...MODEL 250DP DUAL PULSE RESISTANCE WELDING POWER SUPPLY 990 280 xi ...

Page 12: ......

Page 13: ...a versatile 250 watt second stored energy capacitor discharge dual pulse power supply which can effectively solve most precision small parts resistance welding problems Its exclusive context sensitive user help screens quickly guide you through even the most complex program Figure 1 1 250DP Dual Pulse Resistance Welding Power Supply ...

Page 14: ...mproves process control by detecting subtle changes in voltage current and power The remote schedule feature allows the 250DP to reliably select weld schedules in automated applications The 250DP can be used with manual user actuated or air actuated weld heads It is a multi voltage unit designed for operation at 100 115 208 or 230 VAC 50 60 Hz Features x Multi function microprocessor control provi...

Page 15: ...rgy to compensate for electrode wear x Schedule protection and system security features protects weld schedules except Schedule 0 from changes by unauthorized personnel x The schedule lock feature allows you to restrict welding to one selected weld schedule x Power up schedule selection allows any of the 128 schedules or the last schedule used to be specified as the default power up schedule x The...

Page 16: ...oot switch on an air actuated system before the end of the welding sequence x The line failure turndown safety feature discharges the capacitor bank when input power is interrupted x The 250DP is protected from radio frequency interference and electromagnetic interference resulting in reliable operation even in high electrical noise environments Input switch debounce circuitry eliminates false tri...

Page 17: ... bench approximately 5 inches behind the weld head Use the cables furnished with the weld head to connect the terminals on the back of the weld head to the appropriate terminals on the front of the 250DP Convention is to connect the lower electrode of the weld head or hand piece to the output terminal and the upper electrode to the output terminal of the 250DP If the weld head cables are unservice...

Page 18: ...ely they must be free from oxidation dirt and or grease see figure 2 2 Figure 2 1 Cable Routing Examples Steel Weld Head Solenoid Cables taped together and routed away from steel structure and electromagnetic field Weld Head Steel Fixture Cables not dressed together and close to steel fixture DON T DO Lower Electrode H older U pper W elding Cable S crew Flat W asher Nut 2 Places Lower W elding C a...

Page 19: ... 25 pin subminiature D type connector used to interface with other Unitek Peco devices C OPTICAL FIRING SWITCH 5 pin receptacle is used to connect the 250DP to weld heads with either a 3 wire firing switch or an optical switch D AIR VALVE DRIVER 2 Provides 24 VAC to control a second Unitek Peco air actuated weld head E AIR VALVE DRIVER 1 Provides either 24 or 115 volts AC to control a Unitek Peco ...

Page 20: ... have two pin firing switch connectors which can be connected directly to the mating connector of the MECHANICAL FIRING SWITCH located on the rear panel of the 250DP Users of manually actuated weld heads which do not have force firing switches must connect the two pins in the mechanical firing switch to an external switch in order to initiate the 250DP Air actuated weld heads which do not have for...

Page 21: ...single regulator installation for a Unitek Peco Series 80 Weld Head Turn the regulator s fully counter clockwise to ensure minimum air pressure Turn on the air supply Repair leaks if necessary All Thinline weld heads are capable of cycling at a rate of 1 weld per second provided that the tubing between pressure regulators and the air cylinder is kept as short as possible Increasing the length of t...

Page 22: ...of the 250DP Weld heads with 4 pin 24 115 VAC connectors can be plugged directly into the power supply Weld Heads with standard 115 volt plugs NEMA 5 15P require an adapter Unitek Peco Model VDAC Valve Driver Adapter Cable When the connection has been made the 250DP will automatically recognize that an air head has been connected Figure 2 4 Typical Solenoid Air Valve Assembly with a Single Regulat...

Page 23: ... assembly to the appropriate 24 volt pins of the receptacle on the rear of the 250DP Refer to Appendix A under Control Signals for detailed information Footswitch Connect either a 1 Level or 2 Level Footswitch to the FOOTSWITCH receptacle located on the rear panel The 250DP will automatically recognize which type Unitek Peco Footswitch has been connected 1 Level Footswitch When the operator fully ...

Page 24: ...used to provide status timing signals to external devices They can also provide an on closed state during a Run state or if there is an alarm Relay 1 can also be used to control a second 24 VAC air actuated weld head Refer to Air Actuated Weld Head Connections for the appropriate hook up connections and figure 4 5 for appropriate jumper connections Relay 2 can provide a 5 to 50 VDC signal When use...

Page 25: ...5 2 4 2 3 2 2 2 1 2 0 Weld schedule select User supplied Programmable Logic Control L1 L2 Initiate Power output Air valve driver 24V AC Return 115V AC Auto sense 1 2 3 4 1 2 1 Firing switch See note 3 See note 2 Weld cables See note 1 See note 4 Weld Head Force firing switch See note 2 Electrodes Air solenoid 24 115V AC Pneumatic input Notes 1 Tie weld cables together 2 For non force fired operati...

Page 26: ......

Page 27: ...ESISTANCE WELDING POWER SUPPLY 990 280 3 1 CHAPTER 3 OPERATING CONTROLS AND SCREENS Operating Controls Figure 3 1 illustrates the layout of the operating controls on the front panel of the 250DP Figure 3 1 Front Panel Controls ...

Page 28: ...menu states this key is used to select the parameter to the right or left of the parameter which is highlighted PROG Causes the 250DP to enter the program state so that you can make changes to Schedules 0 through 127 If a Weld Sentry is installed when PROGRAM is pressed a second time you can make changes to the Weld Sentry programs related to each weld schedule Press PROGRAM to return to the PROGR...

Page 29: ... or x the Weld Sentry Program Line if the Weld Sentry is installed ENTER Use this key to signify that the data entry you have entered using the keypad is complete WELD NO WELD SWITCH Welding current will not flow when this switch is in the NO WELD position However the control will actuate the weld head and execute the welding sequence Squeeze Weld and Hold This switch must be in the WELD position ...

Page 30: ...Pulse 1 energy G Weld counter step count for next schedule H Pulse width of Weld Pulses 1 and 2 I Next schedule number 1 127 in chain J Present state of 250DP K Weld Sentry program lines Program A E last weld results measurement unit upper lower limits Sentry status L Weld function basic repeat or roll spot M Weld counter step count for next schedule N Pulse width of Weld Pulses 1 and 2 O Switchin...

Page 31: ...CHAPTER 3 OPERATING CONTROLS AND SCREENS MODEL 250DP DUAL PULSE RESISTANCE WELDING POWER SUPPLY 990 280 3 5 Figure 3 2 Screen Flow Chart ...

Page 32: ......

Page 33: ... through 127 cannot be changed when the system security is PROTECTED If SCHEDULE LOCK is also ON only the schedule displayed can be used to weld To change system security and or turn OFF SCHEDULE LOCK press MENU and select SYSTEM SECURITY NOTE To override the security code refer to Appendix A under Weld Schedules 8 If appropriate change the output relay configuration with the PROGRAM screen Adjust...

Page 34: ...e which are printed on the side of the weld head 3 To prevent the 250DP from firing until you are ready to weld select NO WELD Remove the workpiece from between or beneath the electrodes 4 Set the force indicator on all Unitek Peco weld heads to 3 For more detailed information on setting up each specific weld head refer to their respective manuals See figures 4 1 and 4 2 for illustrations of typic...

Page 35: ...d cannot begin until the second level of the foot switch and the force firing switch in the weld head close The 250DP will enter a standby state until these conditions are met When the firing force is reached the weld period will start Assuming that an alarm does not occur the welding sequence will continue to completion and the weld head will rise at the end of the hold period If FOOT SWITCH WELD...

Page 36: ...he upper electrode moves at a reasonable rate and does not impact the workpiece hard enough to damage either the electrode or the workpiece If the flow controls interact readjust the air pressure which controls the pressure on the bottom of the cylinder so that it is identical to that set on the other regulator Then adjust the flow control so that the upper electrode does not slam against the bott...

Page 37: ... higher welding force is necessary reset the force indicator on the weld head to a larger number then repeat Steps 9 and 10 12 If a lower welding force is necessary reset the force indicator on the weld head to a smaller number reduce the pressure regulator which controls the air pressure on the top of the air cylinder then repeat Steps 9 and 10 13 If appropriate configure the Weld Sentry Press ME...

Page 38: ...ty menu 17 If you are using a second air actuated weld head a Connect the second air head to Air Valve Driver 2 b There are two jumper headers E10 and E11 located on the lower right hand area of the control printed circuit board Re jumper the headers to the dual air configuration as shown in figure 4 5 c Press MENU and select OPTIONS d Change the weld head type to DUAL AIR e Press PROGRAM and move...

Page 39: ...trolling Factors Heat ENERGY selected on 250DP Time PULSE WIDTH selected on 250DP Number of pulses selected on 250DP Pressure Electrode firing force set on weld head Surface area of electrode faces The effects of excessive or insufficient heat time and pressure on a weld are illustrated in figure 5 1 You should consider the interaction between these basic welding parameters when developing a weld ...

Page 40: ...oderate force setting 3 on a Unitek Peco Weld Head Figure 5 1 illustrates the effect of electrode force on the work piece 3 Adjust the air pressure for air operated weld heads Figure 5 1 Effects of Excessive or Insufficient Heat Time and Pressure HEAT Excessive Insufficient CAUSE PROBLEM Parts Overheating Weak Weld Insufficient Nugget Metal Expulsion Warping Discoloration Electrode Damage FORCE Ex...

Page 41: ...hrome 2 Tantalum 2 Bronze 2 Inconel 2 Nickel 2 Tinned Brass 14 Chromel 2 Invar 2 Nickel Alloy 2 Tinned Copper 14 Consil 11 Iridium 2 Niobium 2 Titanium 2 Constantan 2 Iron 2 NiSpan C 2 Tungsten 2 Copper 14 Karma 2 Platinum 2 Zinc 14 Dumet 2 Kovar 2 Paliney 7 2 Electrode Face Use a flat electrode face for most applications Use a domed face if surface oxides are a problem If either of the work piece...

Page 42: ...the energy of the Pulse 2 Making a Weld CAUTION Always observe safety precautions when welding Wear your safety glasses 1 Select RUN and WELD on the 250DP 2 Position the parts between the electrodes 3 Press the footpedal or footswitch to initiate the 250DP Assuming no weld occurred increase ENERGY in increments of 5 until the parts begin to weld If you are using dual pulse operation increase Pulse...

Page 43: ...Y and save it to the weld schedule you are using Causes of Imperfect Welds Table 5 2 lists the effects of the basic welding parameters on weld quality Table 5 2 Causes of Imperfect Welds Electrode Problem Energy Force Size Time Weak Weld Too Low Too High Too Large Too Short Blow Holes Expulsion Too High Too Low Too Small Too Long Burned Pitted or Cracked Electrodes Too High Too Low Requires Mainte...

Page 44: ...racteristics of some material combinations This effect occurs when welding x Materials with large differences in resistivity such as copper and nickel x Identical materials with thickness ratios greater than 4 to 1 Since polarity can be an important consideration in resistance welding of some material combinations be sure to check the weld schedule results using both positive and negative polarity...

Page 45: ...erance to changes in weld energy Curve B shows a small reduction in strength but considerably more tolerance to changes in weld energy Weld energy current will vary as a result of material variations and electrode wear Curve B is preferred since it shows more tolerance to changes in weld energy and has nearly the same bond strength as Curve C A comparison of weld schedules for several different ap...

Page 46: ... to ensure that the electrode faces are smooth and parallel If you don t the rough surface of the electrode face will have a tendency to stick to the work piece or if the faces are not parallel energy will be concentrated at the point of contact and a blowout will result To dress the electrode tip 1 Select NO WELD 2 On air actuated weld heads reduce the air pressure to a value just sufficient to l...

Page 47: ...also change weld schedules by keying in the appropriate schedule number 000 through 127 CHNG will change lines 6 and 7 of the RUN state screen as shown below a through d to display either x a and c graphic below showing the energy of Pulse 1 for a manual or air head or x b the status of the output relays or x d the status of the Weld Sentry If NO WELD has been selected the legend ű R U N ű in the ...

Page 48: ...mation to be placed on the terminals of the CONTROL SIGNALS connector or x Waiting to be reset to another schedule after a stop command in a chained schedule PROGRAM State In this state the 250DP will allow you to change and save write to permanent memory any weld schedule Press PROG to enter the PROGRAM state which is signified by the legend ű PROGRAM ű in the lower right hand corner of the scree...

Page 49: ... you have made the changes press SAVE to exit to the RUN state and save the changes MENU State In this state the 250DP will display a menu which allows you to select options which are common to all weld schedules to access the Weld Sentry option and obtain general information The OPTIONS selection of the MAIN MENU screen has three sub screens OPTIONS 1 OPTIONS 2 and OPTIONS 3 ...

Page 50: ...ayed in the upper right hand corner Use or to move from page to page Press HELP to return to the previous state NO WELD State The WELD NO WELD switch is in the NO WELD position The 250DP will execute any weld schedule but the capacitor bank will not be discharged and no welding current will flow FIRE State The firing switch in the weld head has closed and the welding sequence is proceeding Weld Fu...

Page 51: ...e or two weld pulses The weld period starts after the second level of a 2 level foot switch closes and after the firing switch in the head closes It includes the time required to recharge the capacitor bank for the second pulse In AC welding a hold period is usually included as part of a basic weld function It allows the electrodes to cool the work piece However the energy level of the 250DP is no...

Page 52: ...state Repeat Function This function provides an automatic repeat of the weld sequence for simple automated air actuated applications It is ideal for volume production which requires a single schedule NOTE Repeat can only be used with an air actuated weld head You should specify the off time so that it is sufficient to allow the weld head to open the electrodes and to allow you to reposition the wo...

Page 53: ...The energy required for the first spot Weld 1 should be less than that required for all subsequent spots Weld 2 in the sequence Rollspot cannot be used in a chain Dual pulse and or Footswitch Weld Abort OFF are not permitted in Rollspot The PROGRAM State Screen for the Rollspot Weld Function In the rollspot application shown on the above screen the welds would not overlap if the rotational speed o...

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Page 55: ...the front panel POWER switch to OFF 2 Disconnect the power supply from its power source 3 Remove the top two screws on each side of the cover 4 Loosen the bottom two screws on each side and lift the cover straight upwards Capacitor Bank Modifications To operate the 250DP as a 125 watt second unit disconnect one half of the capacitor bank This will cause the 250DP to operate as per specifications l...

Page 56: ...he front panel POWER switch to OFF 3 Remove the cover 4 Remove Jumper A connecting the center terminals 5 Remove Jumper B connecting the positive terminals 6 Replace the cover Line Voltage Changes You may reconnect the power supply to operate at different line voltages 100 115 208 or 230 VAC 50 60 Hz To reconfigure the line power input circuitry proceed as follows 1 Set the front panel POWER switc...

Page 57: ... the control printed circuit board x Bead Pins BP1 BP14 and Terminals E2 and E3 located along the top edge of the control printed circuit board x The taps on Charging Transformer T3 located on the floor of the power supply housing refer to figure 7 1 4 Install the correct circuit breaker Refer to Appendix A under Input Output Cable Connections and Fusing 5 Install the line cord plug appropriate to...

Page 58: ...CHAPTER 7 MAINTENANCE MODEL 250DP DUAL PULSE RESISTANCE WELDING POWER SUPPLY 7 4 990 280 Figure 7 2 100 VAC Line Voltage Configuration ...

Page 59: ...CHAPTER 7 MAINTENANCE MODEL 250DP DUAL PULSE RESISTANCE WELDING POWER SUPPLY 990 280 7 5 Figure 7 3 115 VAC Line Voltage Configuration ...

Page 60: ...CHAPTER 7 MAINTENANCE MODEL 250DP DUAL PULSE RESISTANCE WELDING POWER SUPPLY 7 6 990 280 Figure 7 4 208 VAC Line Voltage Configuration ...

Page 61: ...CHAPTER 7 MAINTENANCE MODEL 250DP DUAL PULSE RESISTANCE WELDING POWER SUPPLY 990 280 7 7 Figure 7 5 230 VAC Line Voltage Configuration ...

Page 62: ...ltmeter Keithley Model 2002 or equivalent x Oscilloscope Pre Calibration Procedures Calibration is performed using the instructions displayed on the screen and the HELP messages The procedure consists of verifying power supply voltages and capacitor bank values and adjusting five trimpots on the control printed circuit board As each trimpot adjustment is performed it must be displayed on the scree...

Page 63: ...6 if you are only performing a calibration check 5 Turn R12 and R36 fully counter clockwise 6 Turn R108 R97 and R104 to mid range 7 Press ENTER to display the calibration screen Entering Capacitor Bank Values Press ENTER to display the next calibration screen and follow the instructions on that screen Adjustment Potentiometers Seven trimpots are located on the control printed circuit board These a...

Page 64: ...tive circuit breaker Replace the circuit breaker x Defective charging transformer Replace the transformer x Misconnected charging transformer Refer to figures 7 2 through 7 5 as appropriate to the input line voltage x Capacitor bank Charge the bank with an external 400 volt DC power supply After 5 minutes the steady state current should be less than 10 milliamps If it is not one or more of the cap...

Page 65: ...tory Service Repair Unitek Miyachi provides a repair service for both warranty and non warranty repairs Call the Customer Service Department at the telephone number shown in the Foreword of this manual for a Return Material Authorization number All equipment to be returned to Unitek Miyachi for repair must be shipped PREPAID Please include information concerning the type of problem you are experie...

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Page 67: ...ur capacitors each half bank totaling 1500 μF nominally At full rating the capacitor banks are operated at a voltage dependent on the actual capacitance The following specifications are related to the capacitor bank Output Pulse Characteristics Pulse width and Polarity can be specified for each of 127 weld schedules Internal switching relays are used to implement this feature Pulse characteristics...

Page 68: ...ing circuit during the charge and turndown intervals This helps prevent poor welds caused by firing the power supply before the capacitor bank is properly charged or discharged Line Voltage Regulation Maintains voltage on the capacitor bank within 0 25 of setting for a 13 change from the nominal rated line voltage Turndown Circuit When voltage from the error amplifier exceeds that required to turn...

Page 69: ... been switched off Polarity Selection Positive and negative polarity can be specified for each weld schedule Polarity sets the initial direction of the weld current flow through the workpiece This feature is useful for welding applications which are sensitive to the direction of weld current flow because of dissimilar materials and or materials with thickness ratios greater than 4 to 1 Welding Spe...

Page 70: ...0 210 240 120 124 75 160 160 95 99 100 125 125 65 70 Conditions 25qC Ambient Nominal Line Voltage 60 Hz In dual pulse operation the repetition rate or hit rate for each individual pulse may be calculated as follows RR1 First Pulse Rep Rate Hit Rate RR2 Second Pulse Rep Rate Hit Rate Calculate RR 1 2 Rep Rate Hit Rate for dual pulse operation RR1 RR2 RR 1 2 RR1 RR2 For example if the energy level o...

Page 71: ...0 6 1 2 5 10 20 50 100 0 100 200 300 WATT SECONDS ENERGY INTERMITTENT AND CONTINUOUS REP RATE 125 Figure A 1 Rep Hit Rate with 1500 μF Capacitor Bank 0 6 1 2 5 10 20 50 100 0 100 200 300 200 WATT SECONDS ENERGY INTERMITTENT REP RATE CONTINUOUS REP RATE Figure A 2 Rep Hit Rate with 3000 μF Capacitor Bank ...

Page 72: ...en installed Weld schedules 1 through 127 can be protected from unauthorized or inadvertent changes by Unitek Peco s system security feature When the system security is protected Schedule 0 can still be modified and used as a scratchpad When schedule lock is also turned ON no other schedules can be displayed or used to weld except the currently displayed schedule NOTE If the security code is lost ...

Page 73: ...he main menu a Change System Security Status c Reset Default Parameters b Copy a Schedule d Set Weld Counters Information Information on the following subjects is available to the operator from the main menu a Calibration d Description of Relay Outputs b Installation e Description of Control Signals c Description of Keyboard f Description of Valve Outputs Weld Sentry When the Weld Sentry option is...

Page 74: ...ir actuated weld head Air actuation means that the 250DP will provide a 24 or 115 VAC output which can be used to control an air valve solenoid on an air actuated weld head The 250DP can automatically detect the presence of a Unitek Peco actuated weld head You can indicate the presence of a user supplied non Unitek Peco air head by jumpering Pin 4 to Pin 2 on the VALVE DRIVER connector If Pin 4 is...

Page 75: ... in order to control an air actuated weld head The 250DP will automatically detect whether a Unitek Peco 1 level or 2 level footswitch is connected to the FOOTSWITCH connector located on the rear panel The 250DP assumes that a 1 level footswitch is used if the input to the 2nd level is continuously closed The 250DP determines whether it is connected to a 1 level or 2 level footswitch whenever it e...

Page 76: ... welding sequence The initiation switch must open and re close in order to start the next sequence FOOTSWITCH WELD ABORT OFF is used in automated process control systems where operator intervention is not an issue Firing Switch Type The 250DP can use as an input signal either a x Single pole single throw switch x Double pole double throw 3 wire switch or an x Optical switch The input signal will i...

Page 77: ...eet long It is a Type 2 C 600 volt cable containing two shielded twisted 22 AWG conductors of high flex stranded wire The firing switch connector is a 2 pin Amphenol 80 MC2FI Unitek Peco PN 520 008 with strain relief It mates with an Amphenol 80 MC2M Unitek Peco PN 520 001 Pin 2 is ground Optical Firing Switch Connector This connector is a 5 pin AMP 212044 1 Unitek Peco PN 550 064 located on the r...

Page 78: ...ed that the Force Firing Switch has closed and the Squeeze Period has ended A 1 Level Footswitch combines the functions of both levels of a 2 Level Footswitch Chain Schedules Feature The chain schedules feature is used to automatically change the weld schedule in use to another specified schedule Chain schedules is a system feature and is turned ON using the options menu When chain schedules is tu...

Page 79: ...ast schedule in a chain CAUTION If weld schedules are chained together do NOT change polarity All schedules in the chain must have the same polarity or the relay contacts may be damaged Audible Buzzer During alarm conditions an audible tone buzzer is generated for 5 seconds It can be immediately silenced by pressing RUN It is also used to signal the operator of an incorrect keyboard entry The volu...

Page 80: ...ss inhibit line Alarm conditions are processed in a priority order corresponding to the following list 1 ALARM SCR The output SCR which discharges the capacitor bank into the pulse transformer may be defective 2 ALARM EMERGENCY STOP An emergency stop signal was received via the CONTROL SIGNALS connector 3 ALARM FIRING SWITCH The force firing switch in the weld head either did not stay closed durin...

Page 81: ...rear panel are AMP P N 206430 1 Unitek Peco PN 550 062 The mating plug is an AMP 206429 1 Unitek Peco PN 520 107 which uses a cable clamp Amp 206358 2 Unitek Peco PN 245 084 Air Valve Driver 1 is wired as follows Pin Description 1 24 VAC 2 115 and 24 VAC return 3 115 VAC 4 Air head sensing externally connected to Pin 2 NOTE Connect Pin 2 to Pin 4 on a non Unitek Peco air actuated weld head Control...

Page 82: ...emote Weld Schedule Selection Control Line 23 5 Remote Weld Schedule Selection Control Line 25 6 Relay 2 Input 7 No Connection 8 Relay 1 Input 9 Process and Charge Inhibit 10 Emergency Stop 11 Signal and Chassis Ground 12 Remote Weld Schedule Selection Control Line 24 13 RELAY 2 Return 14 Remote Weld Schedule Selection Control Line 26 15 RELAY 1 Return Emergency Stop Emergency stop or any other ex...

Page 83: ... to remotely clear any error stop alarm Short Pin 9 to Pin 11 momentarily and immediately open the short to clear the alarm Remote Weld Schedule Selection Refer to figure A 6 To use this feature connect the seven control lines from a user supplied normally open contact open collector or TTL logic levels can also be used to mating CONTROL SIGNALS connector Pins 1 2 3 4 12 5 and 14 Connecting any on...

Page 84: ...Schedule 127 1 2 4 8 16 32 64 Connect Pins 1 2 3 4 12 5 and 14 to Pin 11 ground When all input pins are open control of the power supply remains at the front panel When any one of the pins is shorted the front panel controls are disabled The capacitor bank will begin to recharge 60 milliseconds after the end of the previous pulse unless the charge inhibit line is grounded Therefore any change in t...

Page 85: ...cycle In all of the above cases if the relay is programmed to be on closed it will close at the beginning of the scheduled period and open at the end of that period If scheduled to be closed during any successive periods it will not open at the end of the first period but will remain closed during both or all periods for which it is scheduled to be closed The 24 to 115 VAC input and output for Rel...

Page 86: ...5 208 or 230 volt outlet that is capable of supplying the peak currents specified in table A 4 Circuit Breakers Circuit breakers are used to protect the incoming power line The circuit breakers may need to be replaced if the power supply is reconnected for a different line voltage see table A 4 Fuses A amp fuse F1 is located near the top center of the control printed circuit board The 250DP is shi...

Page 87: ...er The energy display accuracy is 0 5 The resolution of the display ranges from 0 1 to 0 6 energy depending upon the amount of energy selected Energy can be displayed in either watt seconds or of 250 watt seconds Cooling Cooling within the housing is provided by a muffin type fan that operates on 115 VAC 50 60 Hz power The air inlet is underneath the unit and exhaust is through the rear panel No r...

Page 88: ...CHNICAL SPECIFICATIONS MODEL 250DP DUAL PULSE RESISTANCE WELDING POWER SUPPLY A 22 990 280 Physical Characteristics Figure A 7 250DP Dimensions NOTE Dimensions are inches centimeters Weight is 99 Pounds 45 Kilograms ...

Page 89: ... driver 2 6 A 14 Control signals A 15 Footswitch 2 7 Mechanical firing switch 2 4 Non Unitek Peco air actuated weld heads 2 7 C continued Optical firing switch 2 4 Second air head 2 7 Controls front panel 3 1 CONTROL SIGNALS connector A 15 Cool time definition A 9 Cooling 250DP A 21 Cover removal 7 1 CPU microprocessor A 21 D Debounce time switch A 11 Declaration of Conformity following CE Operato...

Page 90: ...k A 13 L Line power input 2 1 A 20 Line voltage changes 7 2 Locating system for installation 2 1 M Main menu information A 7 Main menu utilities A 7 Maintenance Electrodes 5 8 Power supply 7 2 Manual Revision Record ii Mechanical firing switch connections 2 4 MENU state 6 3 Microprocessor CPU A 21 Modification 7 1 N Next schedule A 13 NO WELD state 6 4 O Operating controls 3 1 A 21 Operating Instr...

Page 91: ...d schedule A 6 Welding speed A 3 Squeeze time definition A 8 STANDBY state 6 2 States 250DP FIRE 6 4 HELP 6 4 MENU 6 3 NO WELD 6 4 PROGRAM 6 2 RUN 6 1 STANDBY 6 2 S continued Step count A 12 Sticking electrodes 5 5 Switch debounce time A 11 System Default parameters A 8 Features 1 2 Location considerations 2 1 T Technical specifications A 1 Telephone repair service 7 10 Testing destructive 5 7 Thr...

Page 92: ...ontinued Weld Sentry options and utilities A 7 Weld strength profiles 5 7 Welding 5 4 Welding cable installation 2 1 W continued Welding considerations 5 1 Welding parameters 5 1 Welding schedule specifications A 6 Welding speed specifications A 3 Wiring diagram interconnection 2 9 ...

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