How to bench-test a golf buggy motor
Written by the Hawke Electric Vehicles Service Team
Quick answer
Bench-testing a golf buggy motor means checking the windings for continuity, checking for a short from the windings to the motor case, and running a brief spin test from a battery to confirm it turns freely and smoothly. It is a moderate job that takes 30 to 60 minutes with a multimeter, a battery and jumper leads, and it tells you whether the motor or the controller is the fault before you spend on either.
Tools needed
- Digital multimeter
- 12 volt battery for the spin test
- Insulated jumper leads with clamps
- Socket and spanner set
- Safety glasses
- Insulated gloves
- Clamp or vice to secure the motor
What this fixes
A bench test answers one question: is the motor itself faulty, or is the problem in the controller, wiring or solenoid feeding it. It is the test to reach for when a buggy is slow, cuts out under load, will not move, runs rough or noisy, or trips the controller. Confirming a healthy motor points you back at the controller and wiring; confirming a faulty motor saves you fitting a new controller that will not fix anything. This procedure tests the windings and bearings; it does not repair a motor, which is covered by the brush and motor rebuild work.
Tools and parts
Parts
- No parts are needed to test; a spin-test battery and leads are tools
You will need a multimeter set to a low ohms range, a 12 volt battery for the spin test, insulated jumper leads with clamps, a socket and spanner set to free the motor terminals and mounts, safety glasses, insulated gloves and a clamp or vice to hold the motor still. This is a moderate job of 30 to 60 minutes. You can do the meter checks with the motor still on the vehicle if you disconnect its cables, but the spin test is safest with the motor removed and clamped down.
How to do it
1Isolate and disconnect the motor
With the pack isolated and the capacitors discharged, label and disconnect the motor cables. Note which terminals are the armature pair and which are the field pair from your manual, as the markings vary between motors.
ExpectedThe motor is de-energised, the cables are labelled and you know which terminals belong to the armature and which to the field
2Test the armature winding for continuity
Set the multimeter to a low ohms range and measure across the two armature terminals, turning the shaft slowly by hand as you read so the brushes pass over the commutator segments.
ExpectedA steady very low reading, near zero ohms, that stays roughly constant as the shaft turns; an open reading or wild jumps point to worn brushes, a dirty commutator or a broken winding
3Test the field winding for continuity
Measure across the two field terminals with the meter on the same low ohms range.
ExpectedA very low reading, near zero ohms; an open circuit means a broken field winding and a failed motor
4Check for a short to the case
Put one meter lead on a bare metal part of the motor case and touch each motor terminal in turn with the other, on the highest resistance range.
ExpectedNo continuity and a very high or open reading from every terminal to the case; any low reading means a winding is shorting to the case and the motor has failed
5Spin-test the motor from a battery
Clamp the motor down, connect the field terminals to the battery, then briefly touch the armature terminals to the battery for a second or two. Keep clear of the shaft. Swapping the armature connection reverses the direction.
ExpectedThe motor spins up promptly and smoothly for the brief moment power is applied; a motor that will not turn, turns slowly, sparks heavily at the brushes or screeches has a fault
6Check the bearings and free rotation
With the power disconnected, spin the shaft by hand and feel and listen. Then push and pull the shaft in and out and try to rock it.
ExpectedThe shaft turns freely and quietly and coasts to a stop; grinding, roughness, notchiness or noticeable play in the shaft means worn bearings
Check it worked
7Weigh up the results together
Combine the readings: winding continuity, no short to the case, a clean smooth spin and free quiet bearings.
ExpectedAll four good means a healthy motor, so look to the controller, solenoid and wiring next; any failed check identifies the motor as the fault and shows whether it is a brush, winding or bearing problem
When to book an engineer
Book an engineer if the tests show a short to the case, an open winding, heavy sparking or a bad bearing, because those need a motor rebuild or replacement rather than a driveway fix. It is also worth a professional if every motor test passes but the buggy still will not run, since the fault then sits in the controller, solenoid, throttle or wiring, and an engineer can load-test the whole drive circuit. A bench test narrows the fault down; acting on it often needs specialist tools.
Common questions
Can I test a golf buggy motor without removing it?
You can do the multimeter checks in place as long as you disconnect the motor cables first, so the pack cannot back-feed the meter. The spin test is different: the motor lurches when power is applied, so it is safest done with the motor out and clamped to a bench or held in a vice.
What should the winding resistance read?
Both the armature and field windings should read a very low resistance, close to zero ohms, because they are heavy copper windings. Exact figures are too small for a basic meter to show precisely, so treat near-zero as healthy and an open or high reading as a broken winding.
How do I tell a motor fault from a controller fault?
Bench-test the motor. If the windings have continuity, there is no short to the case, and the motor spins cleanly on a battery, the motor is healthy and the fault lies in the controller, solenoid, throttle or wiring. A failed motor test points the other way.
Is it safe to run a motor off a 12 volt battery?
For a brief spin test, yes, with care. A 12 volt supply turns most buggy motors slowly enough to judge whether they run, without the speed of the full pack. Clamp the motor, keep clear of the shaft, and apply power for only a second or two so a shorted motor cannot overheat.
Why does my motor spin but the buggy still will not move?
A motor that passes the bench test but does nothing on the vehicle points to what sits between it and the wheels or the controller: a failed solenoid, a controller fault, a throttle sensor, or a mechanical problem in the transaxle. The bench test has done its job by clearing the motor.
What does heavy sparking at the brushes mean?
A little sparking is normal, but heavy, ringing sparking during the spin test points to worn brushes, a dirty or scored commutator, or a winding fault. Inspect the brushes and commutator first, since those are serviceable; a winding fault means a rebuild.
Did this fix it?
Every guide is written from manufacturer service documentation and workshop practice, then reviewed before publication. Read how we write and review our repair guides.