swapping rotation direction of a ôstabilized shuntö dc motor
swapping rotation direction of a ôstabilized shuntö dc motor
(OP)
We replaced a "stabilized shunt" dc motor.
From what I can tell we have parallel field winding (F1 and F2) connected accross the input voltage.
We also have armature (A1 and A2) in series with Shunt/Stabilizing winding (S1 and S2). Diagram as follows
L1========Arm===StabShunt======L2
| |
| |
=======Field ============
We wired replacement motor same as original, started it up and it rotated backwards.
Our electricians swapped A1 and A2 to change direction of rotation. Then immediately after closing breaker but BEFORE closing contactor we got a ground on our dc bus and I was called in to take a look. I don't think the wiring has any relationship to the ground (there is some moisture present and also one lead touching the term box cover with what appears to be a scrape in the tape at point of contact). But I want to verify the wiring. Off the top of my head I'm not comfortable swapping either of the series items individually since that disrupts their polarity relative to each other... would rather swap both series items together or else swap the field leads F1 and F2. I'll be digging around for some more info, but I figured I'd ask here as well.
Question: Do you think it is ok to swap A1/A2 to reverse direction, or is it preferable to swap F1 and F2?
From what I can tell we have parallel field winding (F1 and F2) connected accross the input voltage.
We also have armature (A1 and A2) in series with Shunt/Stabilizing winding (S1 and S2). Diagram as follows
L1========Arm===StabShunt======L2
| |
| |
=======Field ============
We wired replacement motor same as original, started it up and it rotated backwards.
Our electricians swapped A1 and A2 to change direction of rotation. Then immediately after closing breaker but BEFORE closing contactor we got a ground on our dc bus and I was called in to take a look. I don't think the wiring has any relationship to the ground (there is some moisture present and also one lead touching the term box cover with what appears to be a scrape in the tape at point of contact). But I want to verify the wiring. Off the top of my head I'm not comfortable swapping either of the series items individually since that disrupts their polarity relative to each other... would rather swap both series items together or else swap the field leads F1 and F2. I'll be digging around for some more info, but I figured I'd ask here as well.
Question: Do you think it is ok to swap A1/A2 to reverse direction, or is it preferable to swap F1 and F2?
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RE: swapping rotation direction of a ôstabilized shuntö dc motor
The motor is operated from 250vdc system
Here is a link to instruction manual
http://ww
On page 7/12, I'm thinking I should be looking at the 4th diagram down?
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RE: swapping rotation direction of a ôstabilized shuntö dc motor
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RE: swapping rotation direction of a ôstabilized shuntö dc motor
So, you reverse only the armature leads in a shunt stab motor to change the DOR.
Muthu
www.edison.co.in
RE: swapping rotation direction of a ôstabilized shuntö dc motor
I'll take some time to understand why later...
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RE: swapping rotation direction of a ôstabilized shuntö dc motor
Yes, fig 4 is correct for changing the direction.
Muthu
www.edison.co.in
RE: swapping rotation direction of a ôstabilized shuntö dc motor
Muthu
www.edison.co.in
RE: swapping rotation direction of a ôstabilized shuntö dc motor
It makes sense to me now. If I think of it as cumulative compounded, then the polarity of the shunt field compared to the series/stabilizing field must be preserved (additive). The lead swap on the armature causes reversal of rotation which reverses induced voltage... armature voltage polarity swap cancels armature lead swap and maintains armature voltage in same relationship to the other windings.
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RE: swapping rotation direction of a ôstabilized shuntö dc motor
If you need to change direction on the fly (without reconnecting), you can put the series winding in the diagonal of a rectifier bridge. That is sometimes done in servos where currents usually are small and loss in the diodes doesn't matter much.
Gunnar Englund
www.gke.org
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