Motor Test Equipment, Valid Magnetics Ltd

Can you clarify the readings, where are you measuring the motor voltage exactly. Is the motor a series, parallel or compound motor. What type of hydraulic controller is fitted to the truck? is the lift lever fitted with a pot or just an on/off switch. If the controller is a PWM (or a chopper in laymans terms) then the voltage will be something less than 36V as the basic control here is to vary the pulse width to increase/decrease the voltage to the motor to achieve the desired control. Are there any discrete power switching devices such as GTOs or MOSFETS, BJTs or Darlington transistors, if so it is possible that they are breaking down during switching and hence the voltage delivered to the motor is less than it should be under normal operation.

your test has no value, since the voltage drop across the motor will change with the loads resistance.
If I understand correctly, the voltage he is reading is the voltage drop across the motor, while the motor is being controlled by a chopper.
Test for any ohms less than 100k on the studs and cables. test for very little ohms through each of the 2 sets of stud (should be short between a1-a2, s1-s2and open between s1-a1 and/or a2).

Thank you. No contractors. If I measure the hydraulic motor, it reads full voltage. The battery will stay at full battery voltage even under a load but the hydraulic motor will drop to 14V under a load. I want to make sure the body motor is NG before I have the customer buy a new motor.

If the battery is reading 36V but the voltage at the pump motor is only 14V when engaged then you have a potential drop between the battery and the motor indicating a bad connection in the power circuit between battery and motor.
If the truck has a pump motor contact assy then check the contact tips and coil assy, the tips may be burnt and/or the coil maybe weak resulting in poor contact and the source of the potential drop of 22V. Check all power connections in the circuit. If any of the power cables run under the battery inspect and check for corrosion (which can reduce the effective cross section area of the cables and thus increase their resistance).
Also check the armature for signs of wear (is it black instead of copper colour), check the brushes and spring tensions. Check the field coils for continuity and signs of burning, check for short circuit to motor body.

Thank you all for your help.
I have 36V in the battery which will maintain 36V at all times even when I engage the hydraulic pump motor. When I engaged the pump motor the volts in the pump motor drops to 14V.
Is the motor any good?

You need to start at the battery and look for voltage drop through the entire system. Problem could be a poor connection at a cable end or bad contact tips.

possible problem jumpers in the battery and the motor to check the current and insulation resistance to the housing

If the voltage drops to 16 then the battery has a serious problem. I don't think it has to do with the motor. Measure the voltage of each cell and you will probably find some bad ones.

Yes it travels fine. The hyd motor volts start at 36v and drop to 16v when you use hydraulics. I think the hyd motor in no good. Not sure how to test it.

sounds like you maybe in traction priority. will the truck travel but no hydraulic functions? hook a DMM to the battery connector and watch your voltage drop. if you start out at 36 volts you are already discharged.