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Discussion Starter #1
Upp sent this to the wrong address last time.. Better late

Roland wrote
> > > Motors are inductive loads, where the ampere will rise with increase
> > > voltage
> > >
> > > Unlike resistance loads as a heater, where if you have a 240 v heater
> > > Element at 8 amps, it will become 4 amps at 120 v.
> > >
> > > A motor that it windings are rated for 240 v may use 10 amps where A
Motor
> > > Has its windings rated for 120 V may use 20 amps for the same hp. But
> > > using
> > > Different voltages on the same windings rated for some other voltage
The
> > > Ampere may increase as follows:
> > >
> > > Here is the results of a 180 VDC motor test I did using different
Voltages
> > > At no load:
> > >
> > > Battery Pack Actual Volts Amperes Rpm
> > >
> > > 12 12.6 5 634
> > > 18 18.9 6 1013
> > > 24 25.4 6.2 1390
> > > 30 31.8 6.4 1773
> > > 36 37.8 6.6 2143
> > > 42 44.5 6.8 2521
> > > 48 51.2 7.0 2985
> > > 54 57.5 7.5 3270
> > > 60 63.7 8 3715
> > >
> > > There is a maximum voltage and ampere rating you can go over on a
Motor.
> > > This is call the Service Factor (SF). If 115V motor has a rated SF of
115%
> > > And the motor has a ampere rating of 200 ampere for continuous running


> > > then
> > >
> > > 200A x 1.15 = 230 amps. The 115V motor can run on 115V x 1.15 = 132.25

V.
> > >
> > > On the label for the motor, there should be a Service Factor which may

Say
> > > SF 1.25 for a DC motor. I don't why the ADC and Warp motors do not
Have
> > > Motor label that list the specifications of the motor.
> > >
> > > My General Electric motor does. It list the DC motor as 165 volts at
175
> > > Amps at 32 HP with a SF of 1.25 meaning the over voltage can be about
208
> > > Volts and the over ampere can be 218 amperes continuous.
> > >
> > > Roland

Therefore what I need to know is .
If I chooses to go with 72 volts on my 30volt rated motor hoping to use less

Than half the amps to do the same job .. Will that really be what I get??
According to the above maybe not..

However..

Am I missing that some controllers actually decrease and control the
Actually amps delivered to the motor?
As I was told earlier here . They don't change the amount of amps .. Just
That amount of time that the amps are applied to the motor.. Or are some
Controllers different in that since.. ..
So if I understand what I am herring.. Then also if the actually amps are
Not changed .. If I open my controller up full to achive max speed the
Amount of amps will not be decreased and my poor motor will die If the amps
Raise and double when I raise the volts that I am considering to make my car

With 72 instead do 30volts..

Tanks Mitchell
 

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70 Posts
Discussion Starter #2
The motor controller like I have, a Zilla, the battery ampere may be 50 amps
at 180 volts or 50 x 180 = 9000 watts. The motor ampere is at 200 amps at
45 volts or still 9000 watts.

So your 30 volt motor may have a 400 motor amp load at 30 motor volt which
is about 12000 watts would be about 90 battery volts at about 130 battery
amps on a 96 volt battery pack if you program the controller for the maximum
voltage you want.

The 12000 motor watts could be the full load required for acceleration or
hill climbing. During cruse it could be 1/2 of that.

A 72 volt battery pack, the motor volts may go to 24 volts and the motor
ampere will go to 12000/24 = 500 amps at maximum load. The battery voltage
may be 65 volts at 12000/65 = 185 battery amps.

If you apply a full 72 volt to the motor, the motor ampere could be 12000/72
= 166 motor amps, that is at the same 12kw rating. The only limitation is
the maximum voltage and ampere rating of the controller.

Roland




----- Original Message -----
From: "Phelps" <[email protected]>
To: <[email protected]>
Sent: Tuesday, July 31, 2007 7:22 PM
Subject: Trying again


> Upp sent this to the wrong address last time.. Better late
>
> Roland wrote
> > > > Motors are inductive loads, where the ampere will rise with increase
> > > > voltage
> > > >
> > > > Unlike resistance loads as a heater, where if you have a 240 v
> > > > heater
> > > > Element at 8 amps, it will become 4 amps at 120 v.
> > > >
> > > > A motor that it windings are rated for 240 v may use 10 amps where A
> Motor
> > > > Has its windings rated for 120 V may use 20 amps for the same hp.
> > > > But
> > > > using
> > > > Different voltages on the same windings rated for some other voltage
> The
> > > > Ampere may increase as follows:
> > > >
> > > > Here is the results of a 180 VDC motor test I did using different
> Voltages
> > > > At no load:
> > > >
> > > > Battery Pack Actual Volts Amperes Rpm
> > > >
> > > > 12 12.6 5 634
> > > > 18 18.9 6 1013
> > > > 24 25.4 6.2 1390
> > > > 30 31.8 6.4 1773
> > > > 36 37.8 6.6 2143
> > > > 42 44.5 6.8 2521
> > > > 48 51.2 7.0 2985
> > > > 54 57.5 7.5 3270
> > > > 60 63.7 8 3715
> > > >
> > > > There is a maximum voltage and ampere rating you can go over on a
> Motor.
> > > > This is call the Service Factor (SF). If 115V motor has a rated SF
> > > > of
> 115%
> > > > And the motor has a ampere rating of 200 ampere for continuous
> > > > running
>
>
> > > > then
> > > >
> > > > 200A x 1.15 = 230 amps. The 115V motor can run on 115V x 1.15 =
> > > > 132.25
>
> V.
> > > >
> > > > On the label for the motor, there should be a Service Factor which
> > > > may
>
> Say
> > > > SF 1.25 for a DC motor. I don't why the ADC and Warp motors do not
> Have
> > > > Motor label that list the specifications of the motor.
> > > >
> > > > My General Electric motor does. It list the DC motor as 165 volts at
> 175
> > > > Amps at 32 HP with a SF of 1.25 meaning the over voltage can be
> > > > about
> 208
> > > > Volts and the over ampere can be 218 amperes continuous.
> > > >
> > > > Roland
>
> Therefore what I need to know is .
> If I chooses to go with 72 volts on my 30volt rated motor hoping to use
> less
>
> Than half the amps to do the same job .. Will that really be what I get??
> According to the above maybe not..
>
> However..
>
> Am I missing that some controllers actually decrease and control the
> Actually amps delivered to the motor?
> As I was told earlier here . They don't change the amount of amps .. Just
> That amount of time that the amps are applied to the motor.. Or are some
> Controllers different in that since.. ..
> So if I understand what I am herring.. Then also if the actually amps are
> Not changed .. If I open my controller up full to achive max speed the
> Amount of amps will not be decreased and my poor motor will die If the
> amps
> Raise and double when I raise the volts that I am considering to make my
> car
>
> With 72 instead do 30volts..
>
> Tanks Mitchell
>
>
 

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70 Posts
Discussion Starter #4
--- Zeke Yewdall <[email protected]> wrote:

I'm not sure exactly what yours is like, but it
> should have four
> terminals on it, not just two like a typical series
> motor. My big GE
> sepex motor has four -- two for the field and two
> for the armature.


Hey Zeke

Number of terminals has nothing to do with how many
terminals it has. Two terminaled motors are designed
to run in just one direction while four terminals
allows you to reverse the motor. Series, sep-ex, and
shunt wound reffer to how the fields are wound. In
fact there are several forklift motors with the same
armatures, brushes, housings, pole shoes, etc but is
available in either series or sep-ex field coils.

Anyway I ran across this thread and wanted to offer
some thoughts.

Hope this helps
Cya
Jim Husted
Hi-Torque Electric



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