Car lift problem

[leveled]

Mine does.

yes and it should, i have questioned this. But if it was at max pressure already could the motor actually start from a dead stop?

 

[Peter 315]

yes and it should, i have questioned this. But if it was at max pressure already could the motor actually start from a dead stop?

I don't think it can start from max pressure , The check valve holds pressure but from the pump to the check valve should have low pressure correct ?

 

[ovrszd]

Simply stated, the pump must be able to produce more pressure than the pressure created by the max rated load of the lift. If not you are unable to lift, stop, resume lift.

Mine performs that task without hesitation.

 

[mike48130]

So the next time you go out there, create the stall situation again, then pull the lower lever right after to see if it will start. This would releive the pressure as it is trying to start.

Can you explain how you tested the capacitor?

So tonight, I went to my dad's to plow the snow. I get there, and the house is cold. Furnace not running, the fan motor blew the breaker and would not start and kept tripping the breaker. He has an old big house with a 7,000 CFM blower and a 220V 3HP motor. I replaced it last year since it was acting up and blowing the breaker even with a new capacitor. So today, the capacitor was dead, and I did have a spare, so swapped it out and started right up. I have a digital capacitor tester, and it shows it is dead.

But, it sounds just like your issue. I think you have a motor issue or the pump is jamming somehow. If you had a bad hose or cylinder, you would still get some movement but slow especially since you can raise and lower it without a load. For it not to start at all I think it points to the pump or motor.

 

[ovrszd]

This really perks my interest. I'll wake up tonight thinking about it.

 

[BertZegers]

We tested the motor and it draws 60 amps when stuck, which we decided that it was not a motor problem, because it is using 6 times the regular working amps. When running it only uses 11 amps. I tested this with a clamp meter. I keep going back to the hose being the problem. I am still waiting on the manufactures opinion. I am really not sure but i learned a lot so far.

All the focus is on electrical or hydraulic, but don't rule out mechanical.

You say that 60 amps is 6 times the the working amps, which makes the working amps 10 Amps.
You measure 11 or 12 amps, which would indicate that the motor is 10% or 20% overloaded. In the video it sounds "normal" during the first push, (startup with low load on motor/pump)
But the motor has not enough start up power (the second push) to lift load. This could be a mechanical problem in cables, sheaves or...

IMPORTANT; What are the working amps or full load amps FLA on the motor plate?
Can you post a picture of the motor plate? If the 11 amps is more than FLA, than there is a hydraulic restriction or a mechanical problem.

Lift the platform to 5 feet high from the floor, then stop. Make sure platform is locked in the safeties, inspect the cylinder for abnormalities, than loosen the connection on the cylinder, than see if oil squirts out when you start the motor/pump. If yes, than there is no restriction towards the cylinder.
When the platform is locked in the safeties, you should be able to pull some slack in the cables ( with lever in "lower" ) and check the whole cable/sheave system.

 

[leveled]

Simply stated, the pump must be able to produce more pressure than the pressure created by the max rated load of the lift. If not you are unable to lift, stop, resume lift.

Mine performs that task without hesitation.

It has worked well for the last 8 years i have lifted my 9500 lbs. excavator on it. plenty of big trucks.i feel its gonna be a odd issue. I am not sure

 

[ovrszd]

It has worked well for the last 8 years i have lifted my 9500 lbs. excavator on it. plenty of big trucks.i feel its gonna be a odd issue. I am not sure

I agree. I call this the KISS principle. Keep It Simple Stupid.

 

[mike48130]

All the focus is on electrical or hydraulic, but don't rule out mechanical.

You say that 60 amps is 6 times the the working amps, which makes the working amps 10 Amps.
You measure 11 or 12 amps, which would indicate that the motor is 10% or 20% overloaded. In the video it sounds "normal" during the first push, (startup with low load on motor/pump)
But the motor has not enough start up power (the second push) to lift load. This could be a mechanical problem in cables, sheaves or...

IMPORTANT; What are the working amps or full load amps FLA on the motor plate?
Can you post a picture of the motor plate? If the 11 amps is more than FLA, than there is a hydraulic restriction or a mechanical problem.

Lift the platform to 5 feet high from the floor, then stop. Make sure platform is locked in the safeties, inspect the cylinder for abnormalities, than loosen the connection on the cylinder, than see if oil squirts out when you start the motor/pump. If yes, than there is no restriction towards the cylinder.
When the platform is locked in the safeties, you should be able to pull some slack in the cables ( with lever in "lower" ) and check the whole cable/sheave system.

I think if it had a mechanical issue the pump would run against the pressure relief. That is assuming the pressure relief works and set to the correct pressure. But you never know.

I think a pressure gauge would be a good investment rather than throwing parts at it. Surplus center has them cheap.

 

[leveled]

So the next time you go out there, create the stall situation again, then pull the lower lever right after to see if it will start. This would releive the pressure as it is trying to start.

Can you explain how you tested the capacitor?

So tonight, I went to my dad's to plow the snow. I get there, and the house is cold. Furnace not running, the fan motor blew the breaker and would not start and kept tripping the breaker. He has an old big house with a 7,000 CFM blower and a 220V 3HP motor. I replaced it last year since it was acting up and blowing the breaker even with a new capacitor. So today, the capacitor was dead, and I did have a spare, so swapped it out and started right up. I have a digital capacitor tester, and it shows it is dead.

But, it sounds just like your issue. I think you have a motor issue or the pump is jamming somehow. If you had a bad hose or cylinder, you would still get some movement but slow especially since you can raise and lower it without a load. For it not to start at all I think it points to the pump or motor.

I took the motor in to a shop they replaced the start switch to the capacitor, i have tested the capacitor multiple times, even had it professionally tested. if its the motor its going through their front window.:shocked:

 

[ovrszd]

You can test the relief valve by topping out the lift and see if the motor stalls or system goes into relief.

Yeah a pressure gauge can be found locally pretty easy

 

[leveled]

I think if it had a mechanical issue the pump would run against the pressure relief. That is assuming the pressure relief works and set to the correct pressure. But you never know.

I think a pressure gauge would be a good investment rather than throwing parts at it. Surplus center has them cheap.

i know i could really use one.

 

[BertZegers]

So the next time you go out there, create the stall situation again, then pull the lower lever right after to see if it will start. This would releive the pressure as it is trying to start.

Can you explain how you tested the capacitor?

So tonight, I went to my dad's to plow the snow. I get there, and the house is cold. Furnace not running, the fan motor blew the breaker and would not start and kept tripping the breaker. He has an old big house with a 7,000 CFM blower and a 220V 3HP motor. I replaced it last year since it was acting up and blowing the breaker even with a new capacitor. So today, the capacitor was dead, and I did have a spare, so swapped it out and started right up. I have a digital capacitor tester, and it shows it is dead.

But, it sounds just like your issue. I think you have a motor issue or the pump is jamming somehow. If you had a bad hose or cylinder, you would still get some movement but slow especially since you can raise and lower it without a load. For it not to start at all I think it points to the pump or motor.

I agree, it sounds like a bad capacitor, but the OP has tried a new capacitor and had the motor tested. I assume the motor has one start/run capacitor and no internal switch.The motor is drawing 11 amps @ 230 volt, so it takes in 2500 Watt. This energy is delivered to the shaft at about 3 HP. If it is not delivered at the shaft it is converted to heat and the motor would get very hot very fast. The pump is running with no or low load. Could a load get it jammed? I think a hydraulic restriction or a mechanical problem.

 

[leveled]

I agree, it sounds like a bad capacitor, but the OP has tried a new capacitor and had the motor tested. I assume the motor has one start/run capacitor and no internal switch.The motor is drawing 11 amps @ 230 volt, so it takes in 2500 Watt. This energy is delivered to the shaft at about 3 HP. If it is not delivered at the shaft it is converted to heat and the motor would get very hot very fast. The pump is running with no or low load. Could a load get it jammed? I think a hydraulic restriction or a mechanical problem.

I agree, i will test the hose tomorrow. and the pressure relief valve.

 

[BertZegers]

I took the motor in to a shop they replaced the start switch to the capacitor, i have tested the capacitor multiple times, even had it professionally tested. if its the motor its going through their front window.:shocked:

If the motor has an internal switch, it should have more than one capacitor or not? My understanding is that the start capacitor is switched off when the motor is up speed, but the run capacitor is on all the time. Do you hear a click when the RPM's drop when the motor stops?

I am very familiar with European electrical motors, but I have limited experience with switched capacitors like in North American motors, although the basics are the same.

 

[leveled]

If the motor has an internal switch, it should have more than one capacitor or not? My understanding is that the start capacitor is switched off when the motor is up speed, but the run capacitor is on all the time. Do you hear a click when the RPM's drop when the motor stops?

I am very familiar with European electrical motors, but I have limited experience with switched capacitors like in North American motors, although the basics are the same.

I originally tested the start capacitor switch contacts by spark testing the capacitor on start up. which was determined to be bad. i had it replaced. hopefully i do not have to throw it through the front window. lol

 

[BertZegers]

I originally tested the start capacitor switch contacts by spark testing the capacitor on start up. which was determined to be bad. i had it replaced. hopefully i do not have to throw it through the front window. lol

I looked again at your pictures. There seem to be 2 capacitors. One start and one run. Start capacitors should not be engaged longer than a few seconds. The start capacitor might be defective by now, after the failed start attempts. Testing a capacitor by short circuit can damage it.
I think that the motor is trying to start on the run capacitor, but this gives not enough torque to run the load.
Get a new start capacitor, and listen if the centrifugal switch turns on and off. Try this with the "lower" valve open, so the motor does run for sure. It is usually the easiest to hear when the motor is shut off and rpm's go down. If this seams OK than try normally.
What is the FLA on the motor plate?

If the motor starts up with no load and than keeps running with load added, and not starting under load, that would be indicative of a start capacitor problem.

 

[ovrszd]

Yeah, I'm voting start capacitor. That's why I wondered if the shop tested the motor under load. I'm guessing not. If it turns out to be the start capacitor I will be disappointed in the shop for not figuring that out.

 

[aczlan]

I think if it had a mechanical issue the pump would run against the pressure relief. That is assuming the pressure relief works and set to the correct pressure. But you never know.

I think a pressure gauge would be a good investment rather than throwing parts at it. Surplus center has them cheap.

Is there a check valve on the base of the cylinder as well as one on the pump? If so, would suspect that the check valve on the cylinder is leaking by and putting pressure on the pump check valve.

Aaron Z

 

[Rc4510]

I took the motor in to a shop they replaced the start switch to the capacitor, i have tested the capacitor multiple times, even had it professionally tested. if its the motor its going through their front window.:shocked:

did you find the problem i have same lift no problems yet