Re: (ET) Does anyone have the E-15 and E-20 traction motors electrical specs ?

[Rob Brockway <getractor yahoo com>]

 The performance curves on both the E15 and E20 were done at the following 
filed current:
Full 1.9 ampsReduced 1 ampReduced .5 amps
I think the field resistance is about 19 ohms.  If you limit the supply to 
36 volts you should not have a problem with excessive field current.
    The armature resistance is approximately .07 ohms.
Ideally the field weakening should be limited to keep the motor in an 
efficient operating point.

Rob
    On Friday, December 16, 2022 at 01:21:47 PM EST, Chris Zach via 
Elec-trak <elec-trak cosmos phy tufts edu> wrote:  
 
 > So if i read you right, sending a possible 45 amps to the field seems 
 > WAY out of spec and i would be concerned.

I'm trying to think: Without raising the pack voltage would it ever be 
possible to put more current into the field? Also it would just make the 
field stronger with respect to the motor and slow it down even more.

The usual danger is with the opposite direction: If the field is too 
weak then the armature can draw too much current and blow up the motor. 
Thus why we have the relay that drops the field resistors out (and puts 
it back at full power) in the event the armature current gets too high. 
Then that plus the in-series field in the motor going up should slow the 
motor down.

C

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> Message: 1
> Date: Thu, 15 Dec 2022 15:34:08 -0500
> From: john <johnreinhard rochester rr com>
> To: elec-trak cosmos phy tufts edu
> Subject: (ET) Does anyone have the E-15 and E-20 traction motors
>          electrical specs ? Planning Sepex conversion
> Message-ID: <e5074c0c-c144-cc10-06c4-dd5dd83a1751 rochester rr com>
> Content-Type: text/plain; charset=UTF-8; format=flowed
> 
> Hi all,
> 
> I am planning to install a Curtis 1266A SepEx controller into an E-15.
> 
>  From what I have read, I need the motor specs which describe Armature
> current versus field current, to define and program in a field map.
> 
> When I searched Google for this, a long ago (2004) discussion popped up
> where Steve Richardson @ Alltrax asked for same thing to program into
> their controller being designed for the Elec-Trak.
> 
> They DID get a reply from Mike Wallace in KY.
> 
> Someone also asked that these specs get posted more publicly, but if
> that happened, I did not find them.
> 
> Does anyone have this motor info? ?
> 
> [Also, anyone have any idea what the parts are inside the custom
> labelled TO-220? devices inside a Curtis 1266A ?? I have a shorted one
> (TO-220), and the marked number does not pop up on Google.? I assume it
> is a 100 Volt (min) High Current FET.? All the gates get fed through 10
> ohm resistors. (the one feeding shorted TO-220 is blown open). The dual
> transistor that feeds resistor also blown, and the Half bridge driver
> that fed that.? But, the CPU still talks to the programmer, So I thought
> it might be worth a try to fix it.? My current plan is reprogram the
> controller to limit amps by 1/6th lower than original 275A max, and
> remove matching labelled device on the other side of the half-bridge
> circuit. I ohmed out the power circuit board and drew the schematic. But
> the logic board has 10x the traces & devices. & I don't really need the
> whole thing (and I don't have a month of personal energy to reverse
> engineer it), just the circuit from that half bridge driver out to the
> power devices. What I really need is a Curtis 1266A service / repair
> manual. But, I might be successful without that... or else generate a
> bunch more smoke ...? Either way, I still the the E-15 motor electrical
> specs]
> 
> John
> 
> 
> 
> 
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