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Power Train

Testing And Adjusting

Problem 4: Sparks at the commutator and/or
rapid brush wear.

Probable Cause:

1. 

Worn brushes:

Make a replacement of the brushes. See New
Brush Installation And Brush Inspection in
Testing And Adjusting.

2. 

Overheating (too much heat) of the traction motor:

Check for an overload motor or a motor with
defects. See Armature Commutator Inspection
in Testing And Adjusting.
Decrease the current limit (C/L) adjustments if
set too high. See the MicroController System
Operation module.
Test the plugging rate, if set too short it will
cause arcing and wear at the brushes.
The duty cycle is too heavy, change the duty
cycle.

3. 

Defective drive motor:

See Armature Commutator Inspection in Testing
And Adjusting.

a. 

Commutator bars burnt in two or more positions at
180¡ apart because:

(1) Armature bars open.

Make a replacement of the armature.

(2) Motor was stalled against a heavy load while

power discharged and caused the two bars, in
contact with the brushes, to burn.

NOTICE

Too heavy a load can stall the motor, and result in a
failure to the drive motor.

(3) Short circuit in the armature.

See Armature Tests in Testing And Adjusting.

(4) Armature not in balance, out of round, off center

or with high commutator bars. This causes the
brushes to bounce (move up and down).

Make sure the diameter is the same all the way
around and is in center line with the shaft. See
Specifications.

b. 

Dirty motor that has a metallic or carbon dust. this
dust is a conductor which causes electrical shorts,
increase amp draw and decrease drive motor
output:

Remove any dirt with air pressure.

c. 

Brush movement causes arcing and brush wear:

Check the brush springs for cracks, and
overheat signs (blue).
Compare spring force with a new brush spring.
Check the brush holder for oversize (larger size
than for brush).
Replace the brush spring if necessary.

d. 

Loose brush leads or motor bus bar connections.

Loose cable connections at motor terminals.
Results are:

(1) High resistance and heating.
(2) Faster brush wear.

Check brushes for tight-connections.
Replace the brushes if leads are loose in
brush material. Check all cable and wire
connections for tightness.

e. 

Wrong grade of brushes installed that are not
adaptable to the motor:

Make sure all the brushes are of DAEWOO
standards. Do not use other brands of brushes.

f. 

Possibly heavy working condition that causes too
much motor heat and rapid brush wear:

Make a replacement of the brushes and make
sure the brushes are seated. See New Brush
Installation and Brush Inspection in Testing And
Adjusting.
Check the brush springs for the correct
installation and for the correct spring usage. Too
strong a spring rate will increase amperage
draw and brush wear rate. 
Prevent operation in stall condition. Excessive
(too much) duty cycle which increases motor
temperatures and rapid brush wear.

4. 

Overload of the drive motor such as: towing loads,
constant ramp operation, chiseling (hydraulic
actions that are not practical) loads and dragging
(pull or push loads on the ground) loads:

Operator training for better working practices.
Add an auxiliary cooling to the drive motors.

5. 

Current limit (C/L) set too high that causes too
much current consumption through motors in the
transistor range:

Decrease the current limit (C/L) adjustment to
the correct setting, see the MicroController
System Operation module.

6. 

Drive motor, armature or field windings have a
defect that results in high current draw at low
torque output:

See Armature Tests and Field Coil and Terminal
Tests in Testing And Adjusting.

11

Summary of Contents for B20S-2

Page 1: ...Specifications Systems Operation Testing Adjusting Disassembly Assembly LiftT rucksPowerT rain B20S 2 B25S 2 B30S 2 BC20S 2 BC25S 2 BC30S 2 SB2025E01 Aug 1999...

Page 2: ...owing symbol Improper operation lubrication maintenance or repair of this product can be dangerous and could result in injury or death Do not operate or perform any lubrication maintenance or repair o...

Page 3: ......

Page 4: ...p Adjustments 21 Pinion Bearing Adjustment 24 Pinion Depth Check 24 Pinion Installation 22 Power Transfer Group 21 Power Transfer Group Bearing And Gear Clearance Backlash Adjustments 25 Troubleshooti...

Page 5: ......

Page 6: ...B BC MODEL Lift Trucks consists of three main components drive motor 3 power transfer group 2 and final drive 1 Electric storage batteries are used as a power source for drive motor 3 The drive motor...

Page 7: ...tant terminals on motor frame 7 On the outside of the motor frame is cover 2 that can be removed for easy access to the brushes and the commutator Field coils 6 are fastened to the inside of the motor...

Page 8: ...gears turn the axle shafts The power transfer group is used to send the power from the electric drive motor to the wheels When one wheel turns slower than the other the power transfer group lets the...

Page 9: ...b 2 The gear teeth of hub 2 are on the inside diameter of the hub which causes the rotation of the hub to be the same as the axle shafts The reduction in size between the axle shaft and the hub causes...

Page 10: ...l failure or an overload of the motor is present personnel must not breathe the toxic fumes which are a product of the burnt insulation All power must be disconnected from the motor before any inspect...

Page 11: ...ome defective control panel failure or drive fuse to go bad Problem 3 Neither traction or hydraulic will last through a complete normal work period Probable Cause 1 Too small a battery equipped in the...

Page 12: ...acks and overheat signs blue Compare spring force with a new brush spring Check the brush holder for oversize larger size than for brush Replace the brush spring if necessary d Loose brush leads or mo...

Page 13: ...the motor with heat to 90 C 194 F 3 Grades of brushes mixed Make sure all the brushes are of DAEWOO standards Do not use other brands of brushes Problem 7 Lift truck moves faster in one direction tha...

Page 14: ...ing Probable Cause 1 Lubricant not to the specified level 2 Wrong type of lubricant 3 Wheel bearings out of adjustment or have a defect 4 Bevel gear and pinion not in adjustment for correct tooth cont...

Page 15: ...ll Brushes 1 Brushes NOTICE Installation of the wrong brushes can cause early motor failure Always make sure the correct DAEWOO brushes are installed 5 Install new brushes 1 Make sure the brushes move...

Page 16: ...e of each brush At least 85 of the brush contact surface of each brush must show wear If necessary do Steps 8 through 11 again until the correct wear can be seen on the brush contact surface NOTICE Ne...

Page 17: ...pressed pressure air Do the test for grounds again If there is still an indication of a ground make a replacement of the armature Open Circuit Test Open Circuit Test 1 Put the digital multimeter Funct...

Page 18: ...s will cause fast brush wear Threads on the Commutator Surface Threads grooves that look like threads on the commutator surface will also cause fast brush wear Grooves on the Commutator Surface Groove...

Page 19: ...an open field coil Ground Test Ground Test 1 Field Terminal 2 Motor housing 1 Put the digital multimeter Function Range Switch on the 20M resistance scale 2 Put one test lead to either outer field ter...

Page 20: ...ance scale 2 Put one test lead to an outer brush terminal 1 and the other test lead to the motor housing 2 There must be more than one megohm resistance 3 Do the test again with one test lead on the o...

Page 21: ...here is an indication that brush wear is too fast see Troubleshooting Problem Sparks at the commutator and or rapid brush wear for probable causes of this problem 4 Inspect all brushes in the motors M...

Page 22: ...other and must never be installed separately The same identification mark of letters and numbers is put on both the pinion and bevel gear Make sure they have the same identification mark before going...

Page 23: ...ck 3 Bearing cup 4 Bearing cup 5 Bearing cone 6 Pinion gear 7 Bearing cone 8 Locknut 9 Ring 10 Gear 11 Ring NOTE The adjustment procedures that follow only cover the shim set configuration Look for ad...

Page 24: ...t in position 23 PINION SHIM CHART New Pinion Marking 10 08 06 04 02 0 02 04 06 08 10 10 0 0 02mm 0 04mm 0 06mm 0 08mm 0 10mm 0 12mm 0 14mm 0 16mm 0 18mm 0 20mm 0 001 in 0 002 in 0 002 in 0 003 in 0 0...

Page 25: ...ion from nominal marked on end of pinion 77 92 mm 3 068 in required mounting distance 78 10 mm 3 075 in actual mounting distance from Step 3 77 92 mm 3 068 in required mounting distance 0 18 mm 0 007...

Page 26: ...que is not correct add or remove shims 1 until it is correct Removal of shims 1 increases the rolling torque Adding shims 1 decreases the rolling torque Record the actual rolling torque after the shim...

Page 27: ...e at the pinion recorded in Pinion Bearing Adjustment Step 6 by 0 63 to 0 88 N m 5 6 to 7 8 lb in 6 Measure backlash again After backlash and preload are correct bend a tab on each lockwasher 7 into a...

Page 28: ...a curve toward the outside To correct this remove shims from under pinion bearing cup After this is done check gear clearance backlash and tooth contact again NOTE Several adjustments of both pinion...

Page 29: ...ads 1 4 5 16 3 8 7 16 1 2 9 16 5 8 3 4 7 8 1 1 1 8 1 1 4 1 3 8 1 1 2 5 16 3 8 7 16 1 2 5 8 1 4 5 16 3 8 7 16 1 2 9 16 5 8 3 4 7 8 1 1 1 8 1 1 4 1 3 8 1 1 2 9 L 3 18 L 5 32 L 5 50 L 10 75 L 10 110 L 15...

Page 30: ...220 L 30 325 L 50 450 L 70 600 L 90 775 L 100 1150 L 150 1610 L 200 2000 L 275 2700 L 400 9 L 3 18 L 5 40 L 7 70 L 10 110 L 15 160 L 20 240 L 35 330 L 50 440 L 65 570 L 75 840 L 110 1175 L 150 1450 L...

Page 31: ...only Opening Temperature 135 L 4 275 L 10 F Closing Temperature 118 L 6 244 L 11 F Drive Motors Model Voltage 1 New Brush Size Minimum 2 New Commutator Minimum Thickness B width B length Brush Length...

Page 32: ...s needed to obtain rolling torque of 0 85 to 1 70 N m 7 5 to 15 0 lb in at the pinion without the differential case assembly 5 Apply LOCTITE NO 609 Sealant to outside diameter of cap 5 prior to assemb...

Page 33: ...and tighten to a torque of 115 L 14 N m 2 Torque for wheel mounting bolts 2 270 L 25 N m 200 L 18 lb ft 3 Torque for bolts 3 holding service brake 55 L 10 N m 41 L 7 lb ft 4 Heat retainer 4 to a temp...

Page 34: ...ts 1 to a torque of 488 L 27 N m 360 L 20 lb ft Drive Tire Installation B Series The optional cushion drive tire must be installed as shown failure to do so will decrease machine stability and cause p...

Page 35: ...ic tire wheel nuts 2 to a torque of 644 L 34 N m 475 L 25 lb ft Use crisscross procedure to tighten the nuts BC Series BC20S 2 BC25S 2 The drive tire must be installed as shown below Failure to do so...

Page 36: ...distance X between the edge of the tire and the outside edge of the wheel Distance X is 21 4 L 0 8 mm 84 L 03 in BC30S 2 wide Axle BC30S Models Wide Axle Install the tire so there is distance Y betwee...

Page 37: ...e wheels On B20 25 30S models remove the brake drum also 2 Remove brake return springs 1 2 and 3 with a suitable brake shoe spring tool 3 Remove brake retainer springs 4 Remove the brake shoes 4 Remov...

Page 38: ...seals 19 and spring 17 from the wheel cylinder Install Brakes Brake Adjuster And Wheel Cylinder 1 Install spring 17 in the wheel cylinder NOTE Put clean brake fluid on the seals and inside of the whee...

Page 39: ...and bolts 9 Tighten the bolts to a torque of 15 L 2 NIm 11 L 1 lbIft 7 Install plungers 8 Connect brake lines 7 and tighten the nuts to a torque of 14 L 2 NIm 10 L1 lbIft 8 Install wheel cylinder cov...

Page 40: ...0W oil on the seal 4 Put the power transfer group in position on the drive axle housing Install the four bolts End By a Install final drives and hubs b Install transaxle Disassemble Power Transfer Gro...

Page 41: ...ockwasher and washer 6 Remove outer bearing cone 17 shims 23 and ring 22 from the pinion shaft Pull pinion shaft 12 out of gear 15 and the housing assembly Remove ring 21 from the pinion shaft Remove...

Page 42: ...ing bores of the housing assembly as shown Install bearing caps 1 and tighten the bolts 4 Measure the distance from the end of the pinion shaft to the bottom of the bar with an inside micrometer Recor...

Page 43: ...end of pinion 77 91 mm 3 067 in required mounting distance 77 91 mm 3 067 in actual mounting distance 77 91 mm 3 067 in required mounting distance 0 mm 0 in thickness of shims that need to be added or...

Page 44: ...shims for setting rolling torque are not shown in the parts book The part numbers are 15 Remove tooling E Measure the thickness of tooling E Subtract from this thickness the recorded end play from st...

Page 45: ...n the carrier and the ten bolts Tighten the bolts to a torque of 70 L 15 NIm 50 L11 lbIft Put bearing cups 3 on the bearing cones 22 Put the carrier assembly in position in the housing assembly Instal...

Page 46: ...lso use Quick Cure Primer if the temperature is below 10 C 50 F End By a Install power transfer group Final Drives And Hubs Remove Final Drives And Hubs Start By a Remove brakes 1 Bend back one of the...

Page 47: ...g 10 from the shaft Install Final Drives And Hubs 1 Install bearing 10 with a press Heat the retainer to 317 to 427 C 700 to 801 F and install it against bearing 10 with a press 2 Install lip seal 9 i...

Page 48: ...7 Put hub and cover assembly 4 in position on the housing and install the bolts that hold it Tighten the bolts to a torque of 55 L10 NIm 41 L 7 lbIft 8 Install bearing 2 locking washer 1 and nut 3 on...

Page 49: ...lift truck in position on tooling A 2 Remove the bolts 1 and wheel 2 3 Remove bolts 3 and adapter 4 4 Remove bolts 5 and cover 6 5 remove the plates and discs 7 from hub 8 6 Remove piston 9 from hub 8...

Page 50: ...nformation 8 Put Loctite No 17430 on the mating surfaces of hub 8 and the transaxle housing Install hub 8 and bolts 10 9 Install piston 9 10 Install the plates and discs 7 into hub 8 11 Put Loctite No...

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