Help with Car lift problem needed - Long!

Can but look and see.

-- Cheers Adrian.

Reply to
Adrian Hodgson
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You've clearly already done the right things and it's strange that there's been no useful result. I begin to wonder whether the 4HP motor is faulty or whether the mechanics have deteriorated to the point of requiring a higher starting torque than the motor was intended to deliver. Has the hoist been shown to work correctly from a normal 3 phase supply?.

If you're considering fitting a single phase motor the present motor will have to be removed and it will be immediately possible to check both the motor and the mechanics. Without ANY doubt an OK 4HP motor removed from the rig should start and run smoothly from the idler motor setup that you have described. It's a pretty improbable scenario but one open circuit winding or a single missing phase connection would exactly duplicate your problem!

Motor starting torque is proportional to the SQUARE of the supply voltage so, whichever system you finish up with, low voltage drop across the feed cable is pretty important.

Good luck jim

Reply to
pentagrid

Thanks Jim;

The 4 HP motor will start without any load on the static converter and although not a true test it shows the motor will start and turn.

From another post there are some things to check on the lift, it could be possible that the mechanics are failing, If I get chance I will try fitting some form of torque driver to see what it needs to turn the screws.

-- Cheers Adrian.

Reply to
Adrian Hodgson

The motor I got from Northern Tools was 2 pole cap start cap run and thus runs at nearly 2500 rpm, the motor pulley is about 1.75" driving a 11" pulley, then to a 2.5" and finally the 8" pulley on the lift. The lift is used to keep a 'Stag' belonging to my daughter off its tyres when not being used, She is also afraid of mice getting into it so likes it high off the ground. The important point that I forgot is that there is not enough starting torque to start lifting the car higher once the full weight is on the lift ( its wheels off the ground). Its fine from starting from ground level (no load on the lift), we found this out after raising it up to work on the brakes and then wanting to raise it higher to check the brake pipes. We had to put the wheels back on, lower the car to the ground and back up again. I see from that Machine Mart sell 4 pole motors (1500rpm) that look identical and I guess this would be better but give a slower lift, maybe a higher starting torque as well. The chap who gave me the lift also gave me a large tub of black grease and said take the covers off and give the screw a good smear before use, probably helps. I put an indicator lamp (neon) across the start cap so that when it goes out I know the motor is up to speed.

Hope this is helpful

John

Reply to
John Belt

Thanks for that John

-- Cheers Adrian.

Reply to
Adrian Hodgson

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