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Curtis B.
Curtis B., Technician
Category: Industrial Equipment
Satisfied Customers: 26054
Experience:  Technican turned service manager on multiple lines of equipment used in industry.
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I have a 24 volt Heff-T-Herman scissor lift. The electric

Customer Question

I have a 24 volt Heff-T-Herman scissor lift. The electric motor for the hydraulic runs but the hydraulic motors do not operate
Submitted: 1 month ago.
Category: Industrial Equipment
Expert:  Curtis B. replied 1 month ago.

Hello! Let's see if we can can work together to get to the root of your question!

Expert:  Curtis B. replied 1 month ago.

The drive motor is running, but no hydraulics. Have you checked the coupler between the motor and the pump? You will need to separate the two parts and check coupler and shafts.

Customer: replied 1 month ago.
Thanks Curtis. I just remove the two bolts holding the impeller? Is the coupler a standard industry one or specific to Heff-T-Herman. Thanks ***** *****
Expert:  Curtis B. replied 1 month ago.

Likley a specific coupler, but not sure. May be same as Genie or others!

Customer: replied 1 month ago.
Curtis I had not work on the unit for the past year. The issue appears to be a problem with power circuit. I put the battteries in and the voltage was good. I checked the coupler it was fine. When iI tried to activate the unit no response. I checked the fuse it was good..I had power to relay (that located by the electric motor. I could not hear solenoids activate when I pushed the switches. Thanks
Expert:  Curtis B. replied 1 month ago.

Does the pump motor come on when you work controls? Are you getting battery voltage to the control valve from the upper or lower controls?

Expert:  Curtis B. replied 1 month ago.

You have 24 volts to the pump motor and the controls?

Customer: replied 1 month ago.
The motor does not come on when i use the control box, I going to check the control box to see if it is receiving power.
Expert:  Curtis B. replied 1 month ago.

If you jump the solenoid, does the pump motor come on?

Customer: replied 1 month ago.
I had no response from either the upper or lower
Expert:  Curtis B. replied 1 month ago.

I would be sure the solenoid works and powers up the motor.

Customer: replied 1 month ago.
As to the solenoids i am not hearing or feeling them activate
Expert:  Curtis B. replied 1 month ago.

two things have to happen. pump has to come on and the solenoids have to open. Do you have 24 volts to the power solenoid from battery pack? If you jump the solenoid, does pump motor run?

Customer: replied 1 month ago.
i will check that -- good idea
Expert:  Curtis B. replied 1 month ago.

OK>

Customer: replied 1 month ago.
Curtis The voltage is 24.8 volts. I bypassed the solenoid the electric motor ran, I have not checked voltage at the control box.Are the solenoids on the negative side of the circuit?
Expert:  Curtis B. replied 1 month ago.

No, solenoids activate with positive. The mounting would be negative.

Customer: replied 1 month ago.
Hi Curtis I checked for voltage at the remote control. I saw no voltage. The batteries are at 24.4 volts
Expert:  Curtis B. replied 1 month ago.

trace back from the control, until you find voltage source . I assume you have voltage at the key switch? and the emergency stops switches are turning on the power?

Customer: replied 1 month ago.
I will check switch. The emergency shut down switch is in the run position
Expert:  Curtis B. replied 1 month ago.

The emergency switch, breaks the circuit, so check to be sure voltage is going through the emerg switch.

Customer: replied 1 month ago.
The emergency switch is probably part of the problem, Hot lead shows 10,5 volts the output side of the switch shows 3.85 volts. The voltage at the key switch shows 10.2 volts. I do not understand why I am different voltages at the key and the ermergenct stop switch. I did bypass the emergency switch but it did not activate the pump.Good idea to check the emergency switch
Expert:  Curtis B. replied 1 month ago.

Yes, get good voltage, 24+ and it will likley work. Trace back till you find full voltage!

Customer: replied 1 month ago.
As I said in my note I am not 24 volts at the key switch or the emergency stop switch. Should I be seeing 24V at both?However I am seeing 24.4 Volts at the batteries. Should be seeing 24V at the key switch and at the emergency stop switch?
Expert:  Curtis B. replied 1 month ago.

You have to have 24 volts at all points, key and controls and solenoids.

Customer: replied 1 month ago.
Curtis Ok I need 24V. Where should i start looking now?
Expert:  Curtis B. replied 1 month ago.

All power starts at battery pack, and the cables start on the positive side of the solenoid, just before the drive motor. So start there, and follow the cables to the connection points and keep using voltmeter until you find loss of voltage, then check cables and connections. I'm thinking bad cable or connection that has corroision.

Customer: replied 1 month ago.
Ok will do, Do you have idea why I am seeing 10V and not the 24V?As I said I am seeing 24 volts at the battery pack? Where does the positive lead from the battery first terminate (at the panel at the back of the unit or at some other location?
Expert:  Curtis B. replied 1 month ago.

At the solenoid, posiitve battery cable, and another cable or group of wires, all get power from the positive side of the battery pack at the first solenoid connection.

Expert:  Curtis B. replied 1 month ago.

Here is link to operators manual for some models, it has schematics that might come in handy. start page 39

Customer: replied 1 month ago.
Do you have a though as to why I am seeing 10 Volts of power instead of 24 volts
Customer: replied 1 month ago.
Thanks Curtis
Expert:  Curtis B. replied 1 month ago.

Bad cable or corroded connection, not letting full voltage! Did you find the operators manuall link I sent?

Customer: replied 1 month ago.
I will check the tomorrow morning. It been a long day. Thanks for your input!
Expert:  Curtis B. replied 1 month ago.

OK>

Customer: replied 1 month ago.
Curtis has been helpful. I am in the process of following on his last suggestion. I do not yet if that will fix the problem
Expert:  Curtis B. replied 1 month ago.

Thanks>