How to connect motor?

[whazza22]

Hi there,

I have very little knowledge on motors as I have never really dealt with them, so im after some advice on how to connect a motor.

The motor is part of an Air Handling Unit with has 2 motors connected together via belts but only 1 running at any time.

One of the motors was faulty and has come back from repair and needs to be reconnected.

From the isolator, there are 6 cables labelled u1,u2,v1,v2,w1 and w2.

I can see all of those connections on the motor terminals but there are no links in place on the motor for star or delta (the lid shows where links go for star or delta)

Does the motor still need to have links in place or is that only when you have 3 cables?

Thanks

 

[Marvo]

It should be as simple as connecting you U1, of the supply to U1 on the motor and so on for the other five wires as well. If you have a six wire supply (seven wire with earth) from the isolator then you would not require any link in the motor terminal box......in fact if there are links you must remove them.

 

[whazza22]

Ok thankyou very much. Is that because the motor can run at low speed or high speed? (or am I completely wrong )

 

[Marvo]

The links are required if the motor is connected to a 3-wire direct on-line supply. With a 6 wire supply the motor is probably on a star-delta system or a speed controller and both of these arrangements don't need links.

Just to complicate matters it's possible to have a DOL motor supplied by six wires but the linking will already be done elsewhere in this case (maybe in the isolator or the control panel where the supply originates from) so extra links in the motor would have no purpose even in this scenario.

 

[benji]

Not enough info,6 wires from isolator do you mean from starter?or is the isolator a local isolator adj. motor?
2 motors linked by v-belts ,connect motor A the same as motor B then CHECK THAT ROTATION of both motors is the same BEFORE replacing v-belts.Can not stress that if you are not experienced enough you should seek assistance with this task.

 

[Knobhead]

As benji has said check the rotation first. A brand new motor you can more or less guarantee direction, rewinds……

 

[whazza22]

Yes, the 6 wires are coming from a local isolator next to the motor

 

[netblindpaul]

Whazza,
What is the motor control/starter?

 

[whazza22]

If the motor rotates in the wrong direction, do I still just swap any two phases? (would this need to be done with both sets of cables or the one?

 

[topquark]

If the motor rotates in the wrong direction, do I still just swap any two phases? (would this need to be done with both sets of cables or the one?

Yep, just swap two phases.

 

[netblindpaul]

topquark,
That depends on the starter!
If you just swap 2 phases (leads) at the motor and there is a Y/D starter then you could get a big bang!

 

[topquark]

If the motor is running backwards you have one of the three phase sequences in the left hand "table" connected to your motor terminals, swapping any two phases will give you either of the three resulting tables, the first table for swapping T1 and T2, the second T1 and T3, the third T2 and T3. From which you can see the phases then end up in the correct sequence.

[TABLE]
[TR]
[TD][B]Terminal[/B]
[/TD]
[TD="width: 27"][B]  T1[/B]
[/TD]
[TD="width: 27"][B]  T2[/B]
[/TD]
[TD="width: 27"][B]  T3[/B]
[/TD]
[TD="width: 86"][/TD]
[TD="width: 39"][B]  T1/2[/B]
[/TD]
[TD="width: 45"][/TD]
[TD="width: 42"][/TD]
[TD="width: 39"][/TD]
[TD="width: 39"][B]T1/3[/B]
[/TD]
[TD="width: 44"][/TD]
[TD="width: 42"][/TD]
[TD="width: 39"][/TD]
[TD="width: 39"][B]T2/3[/B]
[/TD]
[TD="width: 44"][/TD]
[TD="width: 45"][/TD]
[/TR]
[TR]
[TD][/TD]
[TD]3
[/TD]
[TD]2
[/TD]
[TD]1
[/TD]
[TD][/TD]
[TD]2
[/TD]
[TD]3
[/TD]
[TD]1
[/TD]
[TD][/TD]
[TD]1
[/TD]
[TD]2
[/TD]
[TD]3
[/TD]
[TD][/TD]
[TD]3
[/TD]
[TD]1
[/TD]
[TD]2
[/TD]
[/TR]
[TR]
[TD][/TD]
[TD]1
[/TD]
[TD]3
[/TD]
[TD]2
[/TD]
[TD][/TD]
[TD]3
[/TD]
[TD]1
[/TD]
[TD]2
[/TD]
[TD][/TD]
[TD]2
[/TD]
[TD]3
[/TD]
[TD]1
[/TD]
[TD][/TD]
[TD]1
[/TD]
[TD]2
[/TD]
[TD]3
[/TD]
[/TR]
[TR]
[TD][/TD]
[TD]2
[/TD]
[TD]1
[/TD]
[TD]3
[/TD]
[TD][/TD]
[TD]1
[/TD]
[TD]2
[/TD]
[TD]3
[/TD]
[TD][/TD]
[TD]3
[/TD]
[TD]1
[/TD]
[TD]2
[/TD]
[TD][/TD]
[TD]3
[/TD]
[TD]1
[/TD]
[TD]2
[/TD]
[/TR]
[/TABLE]

 

[netblindpaul]

topquark,
What if you have all 6 winding ends coming out of the motor mate.
I can't quite follow your table, sorry not your fault.
If you have winding 1, say U1 & U2, winding 2 V1 & V2, & winding 3 W1 & W2 all separate in the motor, swapping 2 will not help!

 

[whazza22]

On both sets of cables or just the one set? (I have 6 cables from isolator so 2 sets of 3 phases)

 

[topquark]

Sorry if it's missleading, I had thought the question was asking specifically about connection to the motor (as in the thread title and OP).

 

[netblindpaul]

topquark,
IF he has 6 leads from the iso then he probably has a Y/D starter on the end of it, but he has not yet told us.
If I found 6 leads my 1st thought would be Y/D and I would then look into this from there.
If you swap the ends of one pair of windings all you will do is reverse the field in that winding, not good.
If you swap the wrong pair, you could short 2 phases together almost.

 

[netblindpaul]

He is trying to connect the motor, sorry, but he has 6 wire ends to do it as I understand it.

 

[topquark]

He is trying to connect the motor, sorry, but he has 6 wire ends to do it as I understand it.

Ah sorry, I thought that was 6 leads for the two motors, not for the one.

 

[benji]

whazza are you saying you have connected the motor up and it,s going the wrong way or are you asking how to reverse the motor if it goes the wrong way, also where is the starter for the motor?

 

[silva.foxx]

The OP still hasn't stated whether the motor is two-speed or star-delta started.

With star-delta starting, changing the DoR requires a better understanding of the way its wired rather than just swapping phases. The phases have to be swapped in sets (to or at the motor) or on top of the line contactor. If swapped incorrectly, the motor may start in the DoR you require but may try to swap direction in the delta connection, not a good scenario really!

So... just be careful.

note to self: phases is incorrect term for lines L1, L2 & L3.

@ Whazza22... do you know whether you have two speed motor or star-delta starter? Which?

@ Tony... motor sticky... looking forward to that one.

regs// s.f