The hydraulic pump motor of the bendpak two post lift is 3 phase. The engine is sealed so I can not see which way it is going to turn if I connect 3 wires to power line. Does it matter which way the motor is rotating or could I damage the engine if it does not rotate right direction.
3 phase motor connecting
- Thread starter Raul.P
- Start date
wyliesdiesels
Well-known member
It would need to turn in the correct direction.
So theres no way to see the shaft rotation?
Is there an arrow on the motor showing correct rotation?
What kind of power do you have?
You could use a phase rotation meter to check rotation of the feed wires before connecting to motor
So theres no way to see the shaft rotation?
Is there an arrow on the motor showing correct rotation?
What kind of power do you have?
You could use a phase rotation meter to check rotation of the feed wires before connecting to motor
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pancho400cid
Well-known member
There are meters that can let you get the phasing correct before you hook it up. If you aren't in an industrial setting you wont have one.
The common approach is to "bump" the motor to check rotation. Running a pump backwards for a couple of seconds wont hurt it normally. Running it backwards long term might and it definitely won't pump right running backwards. Often there is a rotation direction arrow cast into the pump body or pump adapter.
Hook up the motor and have someone turn it on and then off after a couple of seconds while you watch the motor. I'm assuming you have three incoming power wires (L1, L2 and L3) and maybe neutral. If the motor is running backwards you can normally swap any two L leads to correct it.
The common approach is to "bump" the motor to check rotation. Running a pump backwards for a couple of seconds wont hurt it normally. Running it backwards long term might and it definitely won't pump right running backwards. Often there is a rotation direction arrow cast into the pump body or pump adapter.
Hook up the motor and have someone turn it on and then off after a couple of seconds while you watch the motor. I'm assuming you have three incoming power wires (L1, L2 and L3) and maybe neutral. If the motor is running backwards you can normally swap any two L leads to correct it.
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pancho400cid
Well-known member
Also - If you can't see the shaft but the motor has a cooling fan you can check there. Sometimes it's very hard to tell rotation even if you can see the shaft. A few times I have used a skinny zip tie poked just far enough into the air inlet to tell which way the fan is turning. You have to be careful doing that obviously.
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alfredeneuman
Well-known member
I agree with bumping the motor
No 3Ø motors have a neutral connection.
Swapping any 2 of the 3 legs will always cause the motor to reverse its rotation
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I looked at the engine today again and it has cooling fins on the top. So I can see the rotation from there. The question is - which way it should turn? Looking from the topside where the cooling fins are - should it rotate clockwise of counterclockwise?
nadogail
Well-known member
Bump the motor, and check the rotation.
wyliesdiesels
Well-known member
A 3 phase motor will not have a neutral....
Only you can answer which way it should spin. As has been said You need to look at the pump body, motor nameplate or adapter to see if it tells you the proper direction.
If nothing marked, then look up the manuals or call the manu.
There is no harm in running the motor either way. Lots of 3ph motors are used on equipment that is reversible for that very reason. The pump won't be damaged by the wrong rotation, as long as it has fluid it is lubed.
If it were mine, I'd hook it up and see if the pump makes pressure, if so call it good. if not reverse any two leads as already mentioned.
If it were mine, I'd hook it up and see if the pump makes pressure, if so call it good. if not reverse any two leads as already mentioned.
pancho400cid
Well-known member
Guys -
I was really referring to the incoming power to the lift pump. I agree that small motors do not normally have a neutral connection... like "almost" never (hey - for all I know there are special-purpose small motors out there somewhere with a neutral). I try to avoid "never" and "always" because there are exceptions to every rule. I work for a company that makes electric motors. Some DO have neutral connections, though I grant you they are very large and out-of-the ordinary with wye wound stators.
I was really referring to the incoming power to the lift pump. I agree that small motors do not normally have a neutral connection... like "almost" never (hey - for all I know there are special-purpose small motors out there somewhere with a neutral). I try to avoid "never" and "always" because there are exceptions to every rule. I work for a company that makes electric motors. Some DO have neutral connections, though I grant you they are very large and out-of-the ordinary with wye wound stators.