Vehicle lift stops under load 2.2kw 1ph motor

G

Guinnal

Hi- I am looking for some help/ advice please.I am a mech fitter- not and electrician- all advice gratefully received-
I have a 3 ton, 2 post lift. It is electromechanical - screw type. No Hydraulics. It had a 3 phase motor fitted when I got it, but I only have 240V supply.

I have fitted a second hand Brook Crompton 2.2KW single phase 4 pole motor. Capacitor start/ Capacitor run.(The motor previously ran a pump)

Unloaded the lift works fine. When loaded with a 1200Kg car it will rise about 18" then stops. It will return to lowered position with no problem.

(The original 3phase motor was rated at 3KW, but the lift is available to buy new with a 2.2kw single phase motor. so the 2.2kw motor I fitted should be up to the job- I think. It is physically bigger/beefier than the 3ph motor that it replaced)

The lift is in good mechanical order and isn't binding or jamming under load
It is wired from a 30A supply with 6mm t/e

What can be the problem?

Thanks
 
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Have you tested to see if all 3 phases are present???

Also have you put a clamp meter on all 3 meters to see if they are pulling equal currents.

Does the motor hum under load
 
It is the single phase 2.2kw motor that is now fitted and has the problem. Would there be 3 phases present?
 
I'm sorry I'm a dumb --- and didn't read it properly

I'd suggest a clamp meter on the motor phase to see if there is any deviation from the data plate rating
 
When it comes to electricity- I know which end of the plug goes in the socket- end of knowledge!- so I wouldn't know if you were right or wrong!


When the motor stops and I try to restart, it moves slightly as if it is trying to go but hasn't enough torque. The lights in the garage & house flicker slightly too!!
 
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Ask the lift manufacturer what the gearbox ratio is for the 2.2KW & 3.0KW lifts you may find they are different. Also check the RPM of the 2 motors
 
Yea sounds like windings are shot, data plate will tell amps rated, measure amps on phase line to compare as that will normally show a fault.

Only reservation I have is that this is a live test with the conductors exposed, motor running and under load, basic as it is, if your not confident I would probably farm it out to a spark
 
Tony said:
Ask the lift manufacturer what the gearbox ratio is for the 2.2KW & 3.0KW lifts you may find they are different. Also check the RPM of the 2 motors
Click to expand...

The motor has a 3 belt pulley driving a larger pulley on the top of the main screw which runs inside the lift column. The gear ratio must be the same for both lifts as the part numbers for the pulleys are the same for both 3ph and 1ph versions of the lift.

(The manufacturer's info states that the 240v 1ph models takes 10 seconds longer to reach full height when loaded, i take it that is because the 240v is a 2.2kw motor against the 3ph -3kw motor as opposes to a difference in gearing-?)
 
High Tower said:
Yea sounds like windings are shot, data plate will tell amps rated, measure amps on phase line to compare as that will normally show a fault.

Only reservation I have is that this is a live test with the conductors exposed, motor running and under load, basic as it is, if your not confident I would probably farm it out to a spark
Click to expand...


It is rated at 12.5A on the plate. I will put a meter on it as above.
Thanks

PS- "Windings shot"- new motor or a rewind?
 
i wired a couple of the 3-phase recently on 10a c types

don't know too much

sounds undersized -there's be a fair difference between the 3kw and the 2.2 SP isn't there

the SP would be less efficient
 
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High Tower said:
Are there any Hp ratings for either motor
Click to expand...

On the lift manufactuers motors- 3 phase motor is 3kw (no HP figure is quoted), the single phase motor is 2.2kw (again no HP figure is quoted)

The motor i have fitted is rated at 2.2KW, single phase
 
The Lift is a must have bit of kit in a workshop, therefore I would sugest you go for a new motor rather than rewind. Youll get a better waranty on the motor new, than if you just have it re-wound. WIll pay for itself in notime.....
 
High Tower said:
Yea sounds like windings are shot, data plate will tell amps rated, measure amps on phase line to compare as that will normally show a fault.

Only reservation I have is that this is a live test with the conductors exposed, motor running and under load, basic as it is, if your not confident I would probably farm it out to a spark
Click to expand...

i dont believe the windings to be shot. if they were the motor would not work at all. this motor only stops under load.
 
Hawk81 said:
i dont believe the windings to be shot. if they were the motor would not work at all. this motor only stops under load.
Click to expand...

Hence i havent said it certainly is, it is a possibility, worn brushes etc have seen it a lot on 3ph, current pull drops on a phase, motor starts buy wont run under load.

Good chance its a undersize motor but if it was your money wouldnt you want to test all possabilitys before throwing money away?
 
of coarse test all possible faults. i was simply saying i dont think it is the windings. you said you thought they were shot. either 1 of us could be right. i was just offering another opinion.
 
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Hawk81 said:
of coarse test all possible faults. i was simply saying i dont think it is the windings. you said you thought they were shot. either 1 of us could be right. i was just offering another opinion.
Click to expand...

Without doubt mate, the key to diagnosing faults from a distance without the ability to test for ourselves is to get as many opinions as possible and one will hopefully be right

I have to admit that i became less convinced about a winding fault once the op pointed out in the original post that it was a single phase motor
 
Does the lift manufacturers single phase motor use a continuous rated start winding without a centifugal switch that would switch it out of circuit once the motor has started on most single phase motors

Your motor sounds like it only has a start duty winding that is switched out of circuit and once the load increases on the motor it stalls as the start ( direction ) winding is no longer in circuit and therefore not providing the torque that your lift requires

You will need to check the exact spec of the lift manufacturers motor I would think this has continous rated start winding that will overcome the stall that you are experiencing under load
 
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UNG said:
Does the lift manufacturers single phase motor use a continuous rated start winding without a centifugal switch that would switch it out of circuit once the motor has started on most single phase motors

Your motor sounds like it only has a start duty winding that is switched out of circuit and once the load increases on the motor it stalls as the start ( direction ) winding is no longer in circuit and therefore not providing the torque that your lift requires

You will need to check the exact spec of the lift manufacturers motor I would think this has continous rated start winding that will overcome the stall that you are experiencing under load
Click to expand...


If this was the case with my motor, would it restart for a short period after stopping ( loaded) if i tried switching it on again.

I.E if it runs out of torque as it speeds up then stops,should i be able to raise it by switching on & off etc raising a small distance at a time as the issue repeats itself?
(i hope this makes sense)

If so, then it doesn't. It reaches the same height every time and will not restart at all, going up- although it is obviously trying to.

(I don't have the exact spec of the lift manufacturer's single phase motor)

Thanks for all suggestions so far.
 
Have you checked the motor capacitors are healthy?

Does the motor stall or does it trip the overload protection

If you have run the motor to a point where it has stalled I would not expect it to restart

You do not mention what make or model the lift is which may assist in offering you advice on a fix

Are you running the motor through a contactor and overload if so have you set the overload correctly and wired it properly for single phase
 
UNG said:
Have you checked the motor capacitors are healthy?

Does the motor stall or does it trip the overload protection

If you have run the motor to a point where it has stalled I would not expect it to restart

You do not mention what make or model the lift is which may assist in offering you advice on a fix

Are you running the motor through a contactor and overload if so have you set the overload correctly and wired it properly for single phase
Click to expand...


The motor stalls- IE stops turning, although it it still trying to turn.
I had a 32A breaker in the consumer unit feeding this. I have just changed it for a 20A breaker.

It does not trip the breaker. I tried the lft again a few times just to see if it would trip the 20A breaker- it doesn't

However- as I did this,I noticed that there was liquid dripping out of the start capacitor (Electrolyte?) and the capacitor was quite warm.

The contactor (I take it that's the up/down control switch?) is the original that came fitted to the lift.
Technically, I don't know if it is wired correctly for single phase or not (I'm not an electrician)
Before wiring it, I opened up the contactor and cleaned up the contacts. I put it back together in reverse order. I checked which terminals made contact when, in relation to the position of the Up/Down handle and wired it accordingly. It takes the lift up and down when unloaded with complete ease. Incidentally- it lifts a lighter car further before stalling.

It's a Cascos C3.2. 2.8tonne. Spanish Manufacturer. 1998 model. One owner before me. I have owned it since 2005 though I have only just assembled it. I saw it working, loaded, several times when I bought it.
 
Guinnal said:
The motor stalls- IE stops turning, although it it still trying to turn.
I had a 32A breaker in the consumer unit feeding this. I have just changed it for a 20A breaker.

It does not trip the breaker. I tried the lft again a few times just to see if it would trip the 20A breaker- it doesn't

However- as I did this,I noticed that there was liquid dripping out of the start capacitor (Electrolyte?) and the capacitor was quite warm.

The contactor (I take it that's the up/down control switch?) is the original that came fitted to the lift.
Technically, I don't know if it is wired correctly for single phase or not (I'm not an electrician)
Before wiring it, I opened up the contactor and cleaned up the contacts. I put it back together in reverse order. I checked which terminals made contact when, in relation to the position of the Up/Down handle and wired it accordingly. It takes the lift up and down when unloaded with complete ease. Incidentally- it lifts a lighter car further before stalling.

It's a Cascos C3.2. 2.8tonne. Spanish Manufacturer. 1998 model. One owner before me. I have owned it since 2005 though I have only just assembled it. I saw it working, loaded, several times when I bought it.
Click to expand...

I think this is where the problem is as you are not sure it is wired correctly

I don't think a bigger motor will necessarily overcome a problem of an incorrectly wired one

I think your best solution would be to get an electrician to look at it and check it is wired correctly
 
Give your local rewind shop a call they should be able to test motor for you, I suspect the start capacitor is damage by know but the rewinder will test capacitor for you. If motor tests ok it may be under sized you can still get round the problem by changing the pulley on the motor for a smaller one ie. 2.2kw v 3kw aprox 75%
this would make your ramp 25% slower but give you the required torque.

Problems with your electrics phone a spark problems with a motor phone a winder
 
Thought I would stick my two penneth worth in...As UNG said earlier I think there is a problem with the rating of the motor...as the motor runs up to speed the centrifugal switch will switch out the start winding..this would normally be after the initial start loading has been over come....as you are using it for a lift the load is basically continuous all the time and as such the motor may not be man enough to cope.....may also be the fact the motor cannot get upto speed because of the load to switch out start winding???....then again I could be just waffling which I have been known to do on many occasions!!!!!more info on original motor type would be handy?
 
Just a quick word of warning Guinnal if the single phase motor is newish this isn't a problem, if it's an old second hand one then do not touch the liquid from the capacitor. Some older capacitors contained Polychlorinated biphenyls PCB which is carcinogenic.

Sorry to be a wet blanket
 
Tony said:
Just a quick word of warning Guinnal if the single phase motor is newish this isn't a problem, if it's an old second hand one then do not touch the liquid from the capacitor. Some older capacitors contained Polychlorinated biphenyls PCB which is carcinogenic.

Sorry to be a wet blanket
Click to expand...


Thanks for the heads up - I thought it tasted a bit iffy! I got a new capacitor from RS, same make and model and fitted it.

I put a small honda civic (900KG) on the ramp and it went up to top and back. I stopped it halfway and put it back up again. The lift/ motor had no problem dealing with it. Worked exactly as it should.

I put my nissan 300zx on it (1400kg) - and it lifted about a foot and stalled as before. I'm sure you chaps who diagnosed the motor being under powered had it spot on. As mentioned earlier- it may be that the 2.2kw version from the lift manufacturer has a special motor or is lower geared/ different pulley set.

I tried contacting Cascos UK office who supplied me with spares a year or so ago but they have closed it and have a garage equipment company covering sales and service. They hadn't dealt with the single phase version and couldn't readily advise on the pulley etc. Besides, I would expect the pulley set would cost nearly as much as a motor

I am going to buy a 3kw motor tomorrow, I think (hope) that will be problem solved.

I will update on progress- Thanks for all your advice and help
 

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Vehicle lift stops under load 2.2kw 1ph motor
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