(ET) Nailed

[Christopher Zach <czach computer org>]

Well, it happened sooner than later. I got nailed by my Elec-Trak. 
Shocked on the left hand, and quite painful.

Why you might ask? An Elec-trak is only 36 volts. And we all know that 
36 volts is safe...

Well, I was checking the temp of one of the shunts in the tractor. It's 
an exposed copper strip that was getting very warm under full load. So I 
put my hand in the unit and felt the temp with my finger while bringing 
the tractor up to speed. Then I cut the power to the motor.

*WHAM*

Felt like my hand was bitten. I pulled back; damn it hurt.

What appears to have happened was that when I stopped the motor my hand 
was touching the shunt strip and one of the contactors. My guess is the 
transition of motor from on to off created a big EMF voltage spike 
either in the field or the armature, right thru CZ's hand.

Moral of the story? You can be bitten by 36 volts. I take precautions on 
the Prizm's pack (never pull pack out without first subdividing it into 
60 volt segments *BEFORE* it comes out, all paths to the pack isolated, 
always use gloves, never reaching over the pack, etc) however this 
serves that one can even get bitten on something as innocent as an E20.

Chris