RE: [CAD_CAM_EDM_DRO] Re: QUESTION ABOUT SERIES OR PARALLEL ON STEPPER MOTORS - ref post 52721

Thank you Mariss,
Took a minute or two to digest, but yes I agree! nice to be set thinking.
Nig.

-----Original Message-----
From: Mariss Freimanis <mariss92705@...>
[mailto:mariss92705@...]
Sent: Thursday, February 13, 2003 6:07 PM
To: CAD_CAM_EDM_DRO@yahoogroups.com
Subject: [CAD_CAM_EDM_DRO] Re: QUESTION ABOUT SERIES OR PARALLEL ON
STEPPER MOTORS - ref post 52721


Nigel,

Close but not on the nose.

Parallel nductance is 1/4 of series inductance but the improvement is
only 2-fold, not 4-fold. Here's why:

Properly stated, torque is proportional to "ampere-turns", not just
current. Though the inductance is 4 times smaller, the current has to
be twice as high, making the advantage 2:1 over a series winding.

Mariss

--- In CAD_CAM_EDM_DRO@yahoogroups.com, "Nigel Bailey"
<nigel.bailey@o...> wrote:

As I said at the top, stepper torque is proportional to

> current, so limit on torque will be reached at a much higher speed,
> (theoretically 4X faster) for a parallel connected pair than series.
>
> Whilst on this subject, this is the reason why current controlled

drivers

> are used with supplies at a much higher voltage than the steppers

are DC

> rated at. The high voltage is there to force the current in the coil
> (inductor) to rise more quickly, up to it's limit, but in this case

it's

> limit is controlled by the current controlling driver, rather than

the

> stepper motor coil's DC resistance.
>
> Has that confused anyone further?
> Nig

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