Fwd: Advancing Motor Timing pros/cons/ accel efficiency

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Fwd: Advancing Motor Timing pros/cons/ accel efficiency

KilowattA798
In a message dated 11/6/2012 5:33:20 AM US Mountain Standard Time,
[hidden email] writes:

> Subj:Re: [EVDL] Advancing Motor Timing pros/cons/ accel efficiency
> Date:11/6/2012 5:33:20 AM US Mountain Standard Time
> From:[hidden email]
> To:[hidden email]
> Received from Internet:
>
>
>
> In a message dated 11/5/2012 9:17:13 PM US Mountain Standard Time,
> [hidden email] writes:
> >> Subj:Re: [EVDL] Advancing Motor Timing pros/cons/ accel efficiency
>> Date:11/5/2012 9:17:13 PM US Mountain Standard Time
>> From:[hidden email]
>> To:[hidden email]
>> Received from Internet:
>>
>> Hi Jeff and all,
>
>
> Jeff, You explained it well. In my most recent project I used an 13 inch
> interpole motor because of the abuse it will see. The customer (Bigfoot 20)
> will be on and off the throttle many times during its racing, car crushing,
> jumping ect.This rapid pedaling under hi rpm/hi current would normally arc
> a strait series motor some.
> My CE dragster motor starts the 1/4 mile at about 2 to 3 degrees and
> progresses out to about 9/12 degrees using a small gearmotor.So the brush rack
> is moving most of the 1/4 mile except for the 1st 60 feet. Setting the same
> motor at a stationary 10 degrees (how I bracket race) the dragster looses
> torque and the 60 foot time can gain 15 to 20 percent.
> When one designs this type of moving brush system you must keep the face
> of your brushes in full contact with the comm. otherwise you will not know
> if the arcing is caused by a lifted corner of brush or improper positioning.
> I think Bill Dube and others shuts the controller down when they move the
> brushes.
>
> SORRY about the dragster talk but found it pertinent to the question.
>
> Dennis Berube
>
> >>
>> Hi Bill,
>>
>> I know you like accuracy so I hope you don't mind my comments.
>>
>> Interpoles are located inside the motor frame in between the main field
>> poles.  Those interpoles are excited by coils wrapped around them called
>> comm coils.  These comm coils are connected in series with the armature, not
>> "wired in parallel with the armature".  So the strength of the magnetic
>> force from the interpoles is proportional to the armature current (often
>> called the load) and independent of the RPM.  This actually does not shift
>> any field rather it counteracts flux which would otherwise be present in
>> the commutation zone (interpolar region).  The interpoles (and comm coils)
>> do not contribute to torque production nor do they detract (as does brush
>> advance).  The interpoles and comm coils do consume space in the motor
>> which otherwise could be utilized for materials which would contribute to
>> torque production.
>>
>> Regards,
>>
>> Jeff M
>>
>>
>>
>> ----- Original Message -----
>> From: Bill Dube <[hidden email]>
>> To: Electric Vehicle Discussion List <[hidden email]>
>> Cc:
>> Sent: Monday, November 5, 2012 10:46 PM
>> Subject: Re: [EVDL] Advancing Motor Timing pros/cons/ accel efficiency
>>
>> They do it with "interpoles" between the field poles. These
>> interpoles are wired in parallel with the armature so that as the
>> motor spins faster, the magnetic field in the interpoles ramps up and
>> shifts the angle of the stationary field. Adds complication, cost,
>> and weight to the motor. Also takes up space that would otherwise be
>> occupied by  the regular field coils.
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Subject: Re: [EVDL] Advancing Motor Timing pros/cons/ accel efficiency
Date: Tue, 6 Nov 2012 07:33:20 -0500 (EST)
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_______________________________________________
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