Armature Question - 120V armature on a 240V motor?)

Thread Starter

Avon1330

Joined Nov 6, 2023
2
Hi there. I have a 240v Triton TPT 125 thicknesser (planer) with a faulty motor. In fact one of the commutator fingers is raised and burnt. Unfortunately, 240v replacement motors are on a very ong lead time, whereas 120v armatures are readily available.

My question to the forum is:- 'Would a 120v armature work on a 240v machine ?'

I'm sorry this may seem to be a dumb question, but its worth asking IMHO

Peter
 

ronsimpson

Joined Oct 7, 2019
2,893
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It looks like the motor is the only thing that see 240/120V. I think changing the motor will be OK. The switch will see twice the current but that should be fine. (move power over to 120!) There might be a "start capacitor" which should be changed.
 

MaxHeadRoom

Joined Jul 18, 2013
28,513
My question to the forum is:- 'Would a 120v armature work on a 240v machine ?'
240 on a 120v device will not be good at all. !!

It looks like the motor is the only thing that see 240/120V. I think changing the motor will be OK. The switch will see twice the current but that should be fine. (move power over to 120!) There might be a "start capacitor" which should be changed.
Should not be a start capacitor if it is a Universal motor ?
 

MisterBill2

Joined Jan 23, 2018
17,800
As the motor has an armature it is a universal motor and would not have any use for a start or run capacitor. It might have a noise filter, though.
If 240 volt power is the only option, to make the motor work with a 120 volt armature will require either a step down transformer or a solid state power reducer. 120 volt motors do burn up when run on 240 volt power. It happens withing just a few seconds.
 

MaxHeadRoom

Joined Jul 18, 2013
28,513
Unfortunately you cannot just change the armature to a 120v version and retain the same fields on 120v. You would see a large RPM difference.
They are manufactured as a matched pair.
 

vu2nan

Joined Sep 11, 2014
341
The presence of a commutator indicates that it's an AC / DC motor that's commonly known as a universal motor.

It's not that you need to replace the armature alone but the field windings too.

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Nandu.
 

MaxHeadRoom

Joined Jul 18, 2013
28,513
Hi there. I have a 240v Triton TPT 125 thicknesser (planer) with a faulty motor. In fact one of the commutator fingers is raised and burnt.
Not sure if they are still available, but at one time you could acquire different sizes of replacement commutators.
 
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