Unidirectional or Bidirectional 3

[shlim]

Helo,

I have a motor which drives a coal crusher. Is there a way to determine whether it is a uni-directional or bi-directional motor? I currently only have its rating, specification plate.

I have been trying to look for the information online, but only managed to get the catalouge of the motor, which is basically the details available from its rating plate.

Type : YKK 5003-8
Standard No. : JB/T 10315.2 - 2002

Thank you in advance.

 

[itsmoked]

If it's 3 phase it's unidirectional BUT you can trivially reverse it by swapping any two leads. This is commonly done with a REVERSING motor starter. Turn one contactor on for one direction and the other for the opposite direction. They do need to be mechanically interlocked since turning both ON at the same time can be um.. ah.. unpleasant.

If it's single phase it could be reversible.

Keith Cress
kcress -

http://www.flaminsystems.com

 

[Skogsgurra]

That motor has an air-air cooler. So the direction should not be important.
I would not hesitate to run it either direction.

Gunnar Englund

http://www.gke.org

--------------------------------------
Half full - Half empty? I don't mind. It's what in it that counts.

 

[shlim]

This is a 3-phase motor and they have bi-directional fan blades on the rotor/shaft. Is this is a good indication to confirm that the motor is operable/rotating in both direction?

 

[waross]

Yes.

Bill
--------------------
"Why not the best?"
Jimmy Carter

 

[electricpete]

I agree. Even though there is no externally-evident fan (like TEFC), there is fan to circulate air internally. What style it is I have no idea.

I haven’t worked with water cooled machines, but I have noticed that 2-pole machines are more likely to have directional fans than slower speed machines.


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(2B)+(2B)' ?

 

[electricpete]

Attached is photo of directional (by which I mean unidirectional) internal fan on a 7,000hp 3600rpm open / WP2 motor.

Among larger motors, I'm thinking the 4-pole and above tend to have spider style rotors aid in the cooling and need no axial fan. The 2-pole tend to have solid rotors so need special extra cooling with axial fan . There are also radial blades to cool the endwindings.

At least that's what I've seen. I would double check by inspection or contacting manufacturer.

=====================================
(2B)+(2B)' ?

 

[petronila]

Hi Shim,

Only one comment about your question, usualy when the direction of rotation of one motor is only one you will find an arrow that points to the direction of rotation, in this cases the manufacturer also indicate in the name plate the rotation sequence (example. u-v-w and arrow pointing to direction rotation).

Your above comment is correct " This is a 3-phase motor and they have bi-directional fan blades on the rotor/shaft. Is this is a good indication to confirm that the motor is operable/rotating in both direction " and this point is exactly that you need to confirm when you want to change the direction rotation in one unidirectional motor, i.e. for possible reverse of rotation in one unidirectional motor you most check first if the fan blades are proper or not to provide the air flow for cooling the motor.

Regards

Carlos

 

[1gibson]

Unidirectional fans are quieter than bidirectional fans. Bidirectional fans reduce inventory, and are used when noise and cooling capacity aren't nearing the limit. So, a bidirectional fan isn't a guarantee that the motor is intended to operate in both directions. But unless it has a non-reverse ratchet, I can't think of any other features that would prohibit it.

 

[shlim]

Unfortunately I could not see any arrow showing the direction of rotation on the motor. I would need to recheck this with the manufacturer.

Thanks for all your comments.

 

[squeeky]

This is a uni-driectional fan. The blades slope. Think of this as a centrifugal pump. From your phot this should turn clockwise.