Re: (ET) HELP

[Klein Robert W NPRI <KleinRW Npt NUWC Navy Mil>]

So the problem is solved... But I'm not really sure why.  The contactor I 
received as a replacement was slightly different than the one I removed 
from my C-185 as it had two small symbols next to the small wire posts 
(the wires energizing the internal coil).  I didn't pay to much attention 
to these as it's a coil right?  I mean it works both ways.  Or so I 
thought.  On advice from one of our own I swapped the wires on the 
terminals.  All speeds FWD and REV work and the fuse didn't smoke.  Who 
would have thought.

Anyway, thanks to everyone for their advice.  I love my ET.

Bob Klein
Charlestown, RI




-----Original Message-----
From: Christopher Zach [mailto:czach computer org] 
Sent: Thursday, June 15, 2006 11:29 AM
To: Klein Robert W NPRI
Cc: 'Perry Cain'; elec-trak cosmos phy tufts edu
Subject: Re: (ET) HELP


Klein Robert W NPRI wrote:
> Thanks to Tom Kuffa I was able to swap out the broken bakelite 1A 
> contactor.  Put a new 20amp fuse in the block, engaged the power 
> switch, put the transmission in neutral and pushed the pedal down 
> slowly.  The motor started right up in position one.  Continued 
> pushing and the fuse opened with a flash.  Rechecked my install 
> against the schematic and everything appears OK.  Put in another 
> fuse... Same thing.  The fuse opens in the second speed microswitch.
> 
> Being as I had cooked the terminal off the heavy 1A power wire could I 
> have arc/fused/damaged something else that would cause this short?
> 
> What are the recommended troubleshooting steps?

Well, speed 1 is all resistors in, contactors out. Speed 2 is where 1A 
is closed to bypass resistor 1. Apparently your control circuit is 
blowing at this point.

It sounds like the problem is in the circuit that controls the closing 
of 1A, and not the main wires off 1A. That's what the little 20a fuse is 
blowing over. So check out the small wires that are supposed to trip 1a.

If you remove those wires from the contactor, do they have infinite 
resistance to each other? How about to frame ground? Does the tractor go 
thru the speeds (albeit with resistor 1 close) with the little wires off?

Chris