Re: (ET) Sparks!

[tb <tbamc gbta net>]

<so essentially no current flows through it. No sparks or melting probes 
should result.>

That was my sort of intuitive thought, but…….    On more careful 
inspection I see that the probe was long enough to hit  both the large 
contact and the coil at the same time--and apparently did.  So much for 
that mystery.

Still don't know what's going on though:

I have 38v on ALL coil terminals with throttle in high position, but motor 
is running in only medium (maybe) speed. 

I can definitely hear a change in speed when moving the throttle from low 
to medium, but it seems a fairly small change.

I measure 38v on 1F and 2F large contacts, as expected, but only measure 
2.3v on both 1A lg contacts, even though I've heard  a speed change from 
low.  Same measurement on both ends of 1R (0v on the other end of 2R).

Any thoughts?

Thanks.

Thon




On Jul 22, 2013, at 11:30 AM, Jim Coate wrote:

> Something is odd here... when measuring voltage, the meter is 
> effectively an extremely high value resistor, so essentially no current 
> flows through it. No sparks or melting probes should result. 
> Encountering 36 volts where ever you were testing would be no different 
> than measuring 36 volts across the battery pack.
> 
> Either the meter was set on current (amps) which would indeed produce 
> arcy sparky shows and endanger the meter or blow a fuse, or the one 
> probe was indeed touching two things when you were trying to take a 
> reading. Given how crowded and awkward it is inside the control area, it 
> is pretty easy to do. You can always tape up all but the very tip of the 
> probe if concerned.
> 
> 
> On 7/21/13 1:01 PM, tb wrote:
>> got sparks and nearly burned my probe in 1/2.
> 
> 
> -- 
> Jim Coate
> Free Range Electric
> Elec-Trak parts @ www.ElectricTractorStore.com
> 
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