Multilin PROTECT 4A-120 Instruction Manual Download

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TABLE 3-2 TIME/OVERLOAD CHARACTERISTIC

TRIP TIME VS. OVERLOAD (SECONDS)

Stall Time

Setting

Multiples of Full Load

1.5

1.25

2.5

1.8

2.5

3.6

5.8 10.9 29.2

156

3.6

7.9 11.7 21.9 58.4

140

311

7.5

5.5

7.5 10.9 17.5 32.8 87.6

210

467

7.3

10 14.6 23.3 43.7

116

280

622

12.5

9.1 12.5 18.2 29.2 54.7

146

350

778

10.9

15 21.8 35.0 65.6

175

420

934

17.5

12.7 17.5 25.5 40.8 76.5

204

490 1089

14.6

20 29.1 46.7 87.4

234

560 1245

FIGURE 3-3 THERMAL MEMORY MODELLING

Summary of Contents for PROTECT 4A-120

Page 1: ...MOTOR PROTECTION RELAY INSTRUCTION MANUAL ...

Page 2: ... MOTOR PROTECTION RELAY PATENTS U S 4 241 336 4 224 651 CANADA 1 130 383 COPYRIGHT 1982 1986 1988 MULTILIN ALL RIGHTS RESERVED 215 Anderson Ave PO Box 2700 Markham Ontario Canada L3P 4C7 Tel 905 294 6222 Fax 905 294 8512 ...

Page 3: ... Phase Defeat 17 Factory Service 17 2 10 Environment 17 3 SETUP AND USE 3 1 Control and Indicators 19 3 2 Full Load Control 20 3 3 Stall Time Control 23 3 4 Ground Fault Earth Leakage Level Control 24 3 5 Ground Fault Earth Leakage Time Delay Control 25 3 6 Single Phase Detection 26 3 7 ThermistorTrip Detection 27 3 8 Reset Test Button 28 3 9 Motor Amps Output 29 3 10 Fault Diagnosis 30 4 RELAY TE...

Page 4: ...tion overloads The PROTECT 4A relay is designed to provide protection against the four main causes of motor failure overloads single phasing ground faults earth leakage and overheating ther mistor sensing The Protect 4A relay is economical enough in price that it can be used with low and medium voltage motors bridging the gap between expensive sophisticated relays and economical thermal overloads ...

Page 5: ...2 FIGURE1 1 PROTECT 4A TYPICAL SYSTEM CONNECTION ...

Page 6: ...rotect 4A relay to ensure that the motor protec tion is functioning properly One Protect 4A relay is required per motor Phase and ground fault currents are monitored through current transformers so that motors of any line voltage can be protected The relay is used as a pilot device to cause a contactor or breaker to open under fault conditions that is it does not carry the primary motor cur rent F...

Page 7: ...e is required 5 Mechanical protection of gears pumps fans saw mills cut ters and compressors against mechanical jam 6 Simplified spare parts stocking using one universal model to cover all motor sizes and settings 7 Output of motor current suitable for programmable controller interface 4 20mA The motor phase currents are sensed by 3 conventional 1 amp or 5 amp secondary current transformers CTs If...

Page 8: ... CT 100 5 100 5 CT 150 5 150 5 CT 200 5 200 5 CT 250 5 250 5 CT 300 5 300 5 CT 500 5 500 5 CT 1000 5 1000 5 1 4 ORDER CODE TABLE 1 2 RELAY ORDER CODE RELAY PROTECT 4A 120 PART NO DESCRIPTION PROTECT 4A Standard relay 120 120 VAC control voltage 240 240 VAC control voltage GROUND FAULT CURRENT TRANSFORMERS 1 required for ground fault sensing PART NO DESCRIPTION HGF3 3 Window 2000 1 HGF5 5 Window 20...

Page 9: ...UTES TO CLEAR MEMORY 10SECSTALLSETTING RESET NO LOCKOUT ON TRIP GROUND FAULT EARTH LEAKAGE TRIP LEVEL 1 10A 15 PRIMARYCURRENT FULLSCALE 0 5A MAX WITH CONTROL FULLY ANTI CLOCKWISE TRIP DELAY TIMESAT 25 PICKUP THRESHOLD 30ms 7 30ms TYPICAL 30ms MAX 50 100ms 15ms 200 300 500 750 100ms 15 MOTOR AMPS OUTPUT OUTPUTCURRENCY 4mA 0AMPS 20mA PHASECTRATING ACCURACY LINEAR 5 FULLSCALE MAXIMUMLOAD RESISTANCE 3...

Page 10: ...f rugged plastic with a clear cover for viewing indicators and control settings Phase CTs with 1 amp or 5 amp secondaries should be used These can be standard CTs which are user supplied Dimen sions for CTs available from Multilin are shown in figure 2 2 If zero sequence ground fault detection is required the appropri ate ground fault CT shown in figure 2 3 must be installed FIGURE 2 1 RELAY DIMEN...

Page 11: ...8 FIGURE 2 2 PHASE CT DIMENSIONS FIGURE 2 3 GROUND FAULT CT DIMENSIONS ...

Page 12: ...that goes into slots on the back of the relay is provided with the relay This should be installed to prevent the terminal board from working loose If it is desirable to let operators reset a tripped Protect 4A relay the cover plate should be mounted with the reset hole plug over the reset switch If it is in inconvenient to remove the plug when resetting the unit is necessary an extender shaft can ...

Page 13: ...d onto the Protect 4A relay Protect 4A relays are interchangeable and can be quickly replaced by a standard spare unit regardless of the motor current range Separate phase and ground fault CTs are wired directly to the back of the Protect 4A It is recommended that the ground fault CT wires be twisted together to minimize noise pickup FIGURE 2 5 TYPICAL WIRING DIAGRAM ...

Page 14: ...ging the supply voltage be sure to mark the new voltage on the terminal label for future reference Full accuracy of the Protect 4A relay will be maintained over a wide range of supply voltages which are typically found in in dustrial environments 85 140VAC or 170 275VAC 48 62Hz When the control voltage drops below the minimum voltage the PROTECT 4A output contacts go into the trip condition to pro...

Page 15: ...he auto reset option section 2 9 1 2 6 THERMISTOR INPUT In order to use the thermistor sensing feature the motor being protected must have a suitable thermistor sensor embedded in the stator winding This is normally fitted when the motor is built or rewound although it may be possible to retrofit a thermistor into the end turns of some motors Thermistors exhibit a non linear characteristic and the...

Page 16: ...emperature detectors If no thermistor is used put a jumper between terminals 5 and 6 to prevent nuisance tripping from noise Shielded wire should be used for the thermistor input especially if the wiring is near high current conductors or if the motor is remotely situated Max imum shield effectiveness is obtained if the shield is grounded at one end only FIGURE 2 7 THERMISTOR CHARACTERISTIC FIGURE...

Page 17: ...ss to the Protect 4A controls is desired to prevent settings from being altered by operators tamper proof screws and a special installation tool can be ordered The normal cover screws are replaced with these special screws so that the cover cannot be removed without the tool The cover can also be ro tated 180 degrees and a plug placed over the reset button hole This prevents access to the reset bu...

Page 18: ...t is required to automatically reset when ever a trip occurs set switch S306 on The relay will automatically reset about 5 seconds after tripping Note that the indicators will also reset so that the cause of the trip will not be apparent If auto reset is used ensure that the motor can only be restarted by an operator once the fault has been cleared ...

Page 19: ...a ground fault an alarm condition is registered on the central ground fault monitor but the motors may be allowed to continue running to prevent a production shut down This is possible since the ground fault current is resistance limited however the faulty motor should be repaired as soon as possible because a second ground fault on another phase could cause a phase to phase short circuit resultin...

Page 20: ...ection may be defeated by setting switch S305 off 2 9 5 FACTORY SERVICE Switches S301 S302 are used for factory calibration They should be left off for correct operation 2 10 ENVIRONMENT Precision components and rugged industrial packaging are us ed to ensure that Protect 4A relays will perform accurately and reliably over a wide range of conditions typical of industrial en vironments around the w...

Page 21: ...18 FIGURE 3 1 FRONT PANEL LAYOUT ...

Page 22: ...DELAY CONTROL Sets time ground fault current must exceed level setting before a trip Calibrated in seconds 6 OVERLOAD INDICATOR Set whenever overload or mechanical jam trip occurs 7 UNBALANCE INDICATOR Set whenever single phase trip occurs 8 THERMISTOR INDICATOR Set when thermistor senses an overtemperature and relay trips 9 GROUND FAULT EARTH LEAKAGE INDICATOR Set when ground fault trip or ground...

Page 23: ...me the overload according to the time over load curves of fig 3 2 If the condition persists the relay will eventually trip When the motor is in a normal run state the internal memory begins to discharge to simulate motor cooling Overload trip time will be reduced by the cumulative effect of previous overloads and starting inrush unless the motor has not been overloaded for a period of time in whic...

Page 24: ...3 2 TIME OVERLOAD CURVES P4A STANDARD OVERLOAD CURVES 100000 10000 1000 100 10 1 00 0 10 OVERLOAD FACTOR Multiples of full load control FUL L L OA D CO NTR OL SETTING TIME IN SECONDS 10 100 1000 930112A1 CDR 1 00 ...

Page 25: ...1 8 2 5 3 6 5 8 10 9 29 2 70 156 5 3 6 5 7 9 11 7 21 9 58 4 140 311 7 5 5 5 7 5 10 9 17 5 32 8 87 6 210 467 10 7 3 10 14 6 23 3 43 7 116 280 622 12 5 9 1 12 5 18 2 29 2 54 7 146 350 778 15 10 9 15 21 8 35 0 65 6 175 420 934 17 5 12 7 17 5 25 5 40 8 76 5 204 490 1089 20 14 6 20 29 1 46 7 87 4 234 560 1245 FIGURE 3 3 THERMAL MEMORY MODELLING ...

Page 26: ...motor full load rating which is fairly typi cal If no motor curve data is available this control should be set to the next lowest stall time from that specified for the mo tor Thus for a motor with a rated stall time of 9 seconds at 6 times full load the STALL TIME control would be set to 7 5 sec onds If the stall time is specified at some other inrush current the point can be plotted on the time ...

Page 27: ...occurring on another phase would cause a very high current to flow It will usually be necessary to rewind a motor which develops a fault to earth due to insulation breakdown If no ground fault protection were used however the high fault current could cause severe structural damage to the motor stator or result in the shutdown of the complete bus on which the faulty motor is lo cated Environmental ...

Page 28: ...e bus In a solidly grounded system short time delays should be used to prevent system damage unless the contactor is not capable of break ing the fault current in which case a backup detection system of sufficient interrupt capacity should be allowed to operate first On resistance grounded systems where the fault is limited to safe levels longer time delays can be used if there are no coor dinatio...

Page 29: ...internally set to respond to the large phase current unbalance that occurs under a single phase condition and to trip if this condition persists for five seconds consecutively If an unbalance trip occurs check for a blown fuse loose wiring connections and the incoming supply To prevent nuisance trips on lightly loaded motors when a much larger unbalance level will not damage the rotor the single p...

Page 30: ...rrent To detect the effects of motor overheating due to blocked ventilation high ambient temperature or other unfore seen causes direct temperature sensing is necessary Since temperature rise under these conditions is much slower the temperature detector will accurately sense the actual tempera ture within the motor which would not be true under a rapid heat buildup situation such as locked rotor ...

Page 31: ... situations maintenance staff will correct the fault and put the motor back on line Consequently no lockout after trip is provided since it would be a nuisance When the reset button is pressed after a trip the motor is considered to be cold making it possible to damage a motor by starting tripping and resetting several times Heat build up in this situation would be detected by a thermistor in the ...

Page 32: ...itional current transformers The output of 4 20 mA corresponds to motor cur rent from 0 amps to the full load current of the CT For example if 100 5 phase CTs were used the linear output of 4 20 mA would correspond to phase currents of 0 100 amps Under over load conditions the current is limited to 30 mA maximum For online monitoring the output can be used to drive a pro grammable controller or ch...

Page 33: ...anical jam if enabled locked rotor start incorrect run curve loss of phase by utility blown fuse loose wiring connection worn contactor short between motor windings buildup of material on cooling fins blocked ventilation to motor high ambient temperature too many starts overloads motor winding to case short wiring touching metal ground moisture in motor conductor particles in motor level time sett...

Page 34: ...hase input it is necessary to temporarily connect a capacitor observe capaci tor polarity across the two test points on the terminal board as shown in figure 4 1 Larger capacitors may be substituted The actual value is not critical This shifts the measured values so that all current readings should be multiplied by a factor of 1 5 to set the equivalent 3 phase current Figure 4 1 shows a suitable s...

Page 35: ...32 FIGURE 4 1 SINGLE PHASE INJECTION TESTING FIGURE 4 2 100 AMP CURRENT SOURCE ...

Page 36: ...rns and multiply the current by n through two of the 100 5 CTs shown in figure 4 1 wiring diagram Pass the current source through the two CTs in opposite direction 3 Connect 220 uF 25V capacitor nominal to Protect 4A test points A ve and B ve on the terminal board Observe polarity 4 a Slowly increase the current until the overload indicator starts to flash This is the pickup level The injected cur...

Page 37: ...is should occur at ap proximately three times the full load pickup point Since there is a one second delay between sensing the threshold and ac tually tripping the current must be increased slowly Use the maximum stall time setting and clear the memory be fore doing this test to prevent the overload memory from trip ping before mechanical jam 4 3 SINGLE PHASING Set the FULL LOAD AMPS control to a ...

Page 38: ...fault test system installed in the switchgear Fig 4 3 shows a typical scheme that can be used with the Protect 4A relay Ground fault time delays are controlled by an accurate crystal reference and should be drift free Time delays can be checked using a frequency counter or mechanical cycle timer The scheme will depend upon the equipment used however it will be necessary to use the ground fault cur...

Page 39: ...36 FIGURE 4 3 GROUND FAULT EARTH LEAKAGE TEST ...

Page 40: ...the control should be increased slowly With the thermistor connected or with very high resistances the relay will not trip because a no sensor hold off circuit is activated If an actual thermistor similar to the type used in the motor is available it can be connected instead of the variable resistance When gently heated with a match or heat gun it should cause the relay to trip FIGURE 4 4 THERMIST...

Page 41: ...ding of 75 100 16 4 16 mA Use the setup of fig 4 1 if single phase injection is to be used Multiply all current values by 1 5 and calculate the output as above For example if 200 5 CTs are used apply a current of 200 x 1 5 300 amps through one CT to set an effective input current of 200 amps The output is a current source with a maximum drive voltage of about 8 volts Consequently the programmable ...

Page 42: ...t measured in the motor using a separate ammeter To simulate an overload set the FULL LOAD AMPS control to a value less than the actual motor current and note the trip time from the run curves of figure 3 2 Calculate the amount of overload from period multiple actual current pickup setting Read the trip time from the overcurrent curves of figure 3 2 us ing the curve selected by the STALL TIME SEC ...

Page 43: ... feature Ground Fault Nuisance Trip Capacive motor inrush currents give ground fault signal CT wiring too close to high noise source Increase ground fault level time settings Twist CT wires together and route away from high current cables or use shielded cable Nuisance Unbalance Trip Non sinusoidal waveform May not be suitable for variable speed drive application Check load distribu tion Cannot Re...

Page 44: ...41 FIGURE 5 1 HARDWARE BLOCK DIAGRAM ...

Page 45: ...round fault earth leakage sensing is provided by a fourth cur rent transformer in the current sensing module which encircles the three motor conductors and senses ground faults by the reliable core balance zero sequence method Only if a ground fault is present will this CT give an output which is rectified filtered and compared against a preset value set by the front panel ground fault earth leaka...

Page 46: ...43 FIGURE 5 2 SINGLE PHASE DETECTION FIGURE 5 2a 3 PHASES BALANCED CONDITION FIGURE 5 2b SINGLE PHASE CONDITION ...

Page 47: ...ut of range In case a transient or system malfunction should cause erratic program execution a watchdog timer consisting of independ ent circuitry will reset the microprocessor The correct strobe signals which are only present during normal program execu tion must be received or the watchdog timer will be activated A switch is used to select 120 240 VAC 50 60 Hz for the dual primary power transfor...

Page 48: ...ld representative of a single phase condition for a specific time period an unbalance trip condition occurs In order to generate an inverse curve the three phase average current is squared and integrated over time If the integrated value which represents the thermal heat buildup in the motor exceeds a threshold determined by the stall time setting the relay trips on overload When the motor is stop...

Page 49: ...46 FIGURE 5 3 FIRMWARE BLOCK DIAGRAM ...

Page 50: ...t is returned with all transportation charges prepaid to and from an authorized service centre or the factory Repairs or replacement under this war ranty will be made without charge This warranty shall not apply to any relay which has been subject to misuse negligence accident incor rect installation or use not in accordance with instructions nor any unit that has been altered out side a Multilin ...

Page 51: ...MOTOR PROTECTION Made in Canada PART NO P4A M01 94V 215 Anderson Ave P O Box 2700 Markham Ontario Canada L3P 4C7 Tel 905 294 6222 Fax 905 294 8512 ...

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