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Re: (ET) Running but still odd things, tiny screw head on the thermal breaker, left or right?

Ah ha! Went outside one last time. Tested with the motor lead disconnected in forward, speed 4. Unplugged the deck, tested again, nothing.
So there is a fault between the deck's ground wire and frame ground. Tomorrow I'll check each motor to see if the fault is there, otherwise I have to take apart the whole wire harness. 

Never dull.

On 5/20/2019 7:42 PM, Chris Zach wrote:
So I was checking the tractor and I see there is 36 volts on the relay going to the field in forward, but only 26 volts in reverse. Odd, but it does mean I should have field current.
So I went under the tractor and looked at the motor. Wiggled the two big wires to the motor and the bottom one broke off. Fair enough, it's an old wire. So with the wire off I put the tractor in forward and hit the gas.
Speed 4. Then I remembered: The contactors are on the negative side of the motor, maybe the tractor has a ground fault and it's feeding through a second ground fault in the motor. Ok, find the second ground fault.
Then I put the tractor in reverse. Nothing. Touched the wire to the motor bolt... 

And got a plasma arc that was huge!

Ok, that woke me up FAST.
It's possible I am dealing with a second ground fault here. I know there is one in the motor, probably due to dust and crap and I have been avoiding taking the motor apart. But if there is a second one then yes putting any power to the motor would be full power. 

Maybe it's in the new mower deck wiring.....

C


On 5/20/2019 5:08 PM, Chris Zach wrote:
I took the speed control box off to check. Pressing the first button turns motor on full speed. Pressing buttons 2,3,4 cause *clicks* from the contactors. Kind of neat, but no speed change. 

C


On 5/20/2019 5:01 PM, Harold Zimmerman wrote:

  Stuck switch(es) in the speed control?

On 5/20/2019 4:52 PM, Chris Zach wrote:
Well, yeah just buy a new one from Harold. Blowing your brushes will cost a lot more and my motor was *hot* when I checked it.
That said, what the heck is wrong with my E20 that would cause it to go to speed 4 right out of the box even though I can hear speed 1,2,3 contactors clicking in? Can't be cruise control, that would lock in lower speeds right out of the box. 

C

On 5/20/2019 4:00 PM, Mike Wallace wrote:

Hank,
Considering the advice and help that Harold gave you for free, why not just 
buy a new breaker from him?

Mike in KY

-----Original Message-----
From: Hank Ralston [mailto:Hank RalstonAgency com]
Sent: Monday, May 20, 2019 10:54 AM
To: Harold Zimmerman - Clean Power Supply; elec-trak cosmos phy tufts edu 
Subject: Re: (ET) Running but still odd things, tiny screw head on the
thermal breaker, left or right?
Agree with 3 for three, get a new switch!  Thanks for the tip about keeping it in 3dr during mowing & plowing.  I noticed that it does push up the power usage above 3rd.  the prior problem was getting out of 2nd and not heating up the front end with those resister strips.   It is sort of fun to lift the 
deck and run down our cul-de-sac to clean out the teds after cutting.
Yes the micro switches do wear down after 40+ years and I replaced then all 
about 4 years ago.  Likewise the 2 boards and I of the 2 relays.

Looks like I'll check through the links for a new thermal breaker.

Thanks,
Hank
-----Original Message-----
From: Harold Zimmerman - Clean Power Supply [mailto:cleanpower mailbug com] 
Sent: Monday, May 20, 2019 11:34 AM
To: Hank Ralston <Hank RalstonAgency com>; elec-trak cosmos phy tufts edu 
Subject: Re: (ET) Running but still odd things, tiny screw head on the
thermal breaker, left or right?

  Hank,
  I wouldn't do it. :-)
  Are you sure you have all 7 speeds? You should be running in 3rd speed forward for most of your driving time, which bypasses the power resistor up in the front of the machine. If that resistor is still heating up you are 
probably missing a speed.
  If you are running wide open all the time, that is, with Field Weakening in the circuit, you will be drawing high amps and tripping the circuit breaker 
could be expected.
  I would consider changing out all the switches in the speed control except for the F/R switch (can be done for under 50 bucks) and all the terminals going to cards 1 and 3 (again, not much cost), and if you feel the circuit breaker is over-sensitive, I would replace it with a new one (again, less 
than 50 bucks)  Sincerely,  Harold Zimmerman  Clean Power Supply
  On May 20, 2019 at 9:55am -0400, you wrote:
Finally got my ET15 to go in all speeds forward and back by pushing in all
the shifter micro switch and tighten them down a bit more than they were.
Also tightened some of the clips on the card, just a little at a time, and
put some new fasteners on wire group 49 & 11 that go to the forward and back 
relays.
Still a bit quirky, but at almost 50 years old guess we all were, even with 
new boards and a new relay.
My problem now mirrors yours.  The freak 'n thermal switch seems to be too
sensitive.  I'm very safety minded, (RIT engineering student, commercial Underwriter & Insurance agent),  but I'm tempted to by bass it like I did on 
the many years ago for the snow thrower's circuit breaker.
II see that there is a tiny screw head on the thermal breaker. Can it be 
adjusted?  It so, turn to the left or the right?


Thanks,
Hank
Ralston Agency, Inc.
-----Original Message-----
From: Chris Zach [mailto:cz alembic crystel com]
Sent: Monday, May 20, 2019 8:01 AM
To: Elec-trak list <elec-trak cosmos phy tufts edu>
Subject: (ET) Running but still odd things.
Well, I finally finished refurbishing the deck with a new shell. This one 
has baffles, which means I need to think a bit before putting in my
stiffener bar over the discharge chute (which is currently only supported by the little blanking plate). That part of the deck takes a lot of stress, 
need to think about it a bit.
Fired it up, lot of vibration. Took the blades off, spent some time with a
cheap-o balancer (the Home Depot one doesn't really fit the holes) and took some metal off one side on each blade. Now there is a lot less vibration, 
but not quite perfect. Good enough.
New problem is that the tractor is going into speed 4 right off the bat
even though all contactors are *not* closed. Very weird. In reverse it feels like the field is not coming on, also weird as the motor heats up quickly 
and trips the thermal switch on the motor housing.
I'm not sure if there is a field problem or a short in the main wiring or
something else. It's never dull, I'll check tomorrow when the weather is 
down to the 70's.


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