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Re: [EVDL] Modified K&W BC-20 questions (primary input leads)

Thanks for the advice, Roland.

I don't think it's that serious...the transformer looks like it's fine
to me. The burns are just on the input terminal, which I'm thinking I
should be able to replace independent of the transformer. I don't know
if it's glued on or what...it's on there tight. Figure I'll drop by
radioshack today and see if they've got something similar.

I put some pictures of it up in case you or anybody else wants to have a
look: http://www.fivepointchilidog.com

Thanks

Hunter

Roland Wiench wrote:
>
>
> ----- Original Message -----
> From: "Hunter Cook" <[email protected]>
> To: "Electric Vehicle Discussion List" <[email protected]>
> Sent: Wednesday, October 03, 2007 9:49 AM
> Subject: Re: [EVDL] Modified K&W BC-20 questions
>
>
> > Roland-
> >
> > Very interesting history there...basically just shows that for at least
> > the last 30 years you've been a lot harder core than me. Not that any
> > more proof was necessary ;-)
> >
> > My batteries do not look "super clean." I suppose it's time I tested for
> > leakage. But the first thing on my mind today is what to do about my
> > burned up primary input connections on the boost transformer.
> >
> > Thanks again for all your help,
> >
> > Hunter
>
> Hello Hunter,
>
> If the primary input leads go's directly into the transformer windings and
> the insulation is brittle or gone, you could remove the transformer and take
> it to a motor shop. It may be as simple as re-enameling the core, if the
> transformer test out ok.
>
> If the transformer is a one winding core, then they have a winding machine
> that counts the number of windings as it is remove from the core, and than
> winds new wire on the core. Takes less than 30 minutes to do.
>
> If the leads terminate to a bolt in transformer tab, then you can replace
> these leads with some good high temperature motor leads, that I normally get
> from a motor shop. This type of wire is fine multi strand wire. A No 10 AWG
> may be 52 strand with a 105 C rating or more.
>
> Use a non-insulated solid wire terminal and heat shrink. Sometimes, I had
> transformers or motor leads insulation burn off, and I was able to insulated
> with a 3M high temperature glass tape by wrapping the wire twice half
> lapping the tape. This makes four layers.
>
> If the lead wire has no terminal points and the copper wire itself looks
> brittle, sometimes I could cut the wires leaving about 1 inch from the
> windings and use a non-insulated solid wire inline splice to a flexible
> motor lead wire and heat shrink and glass wrap that connection.
>
> I also spray all these transformer connections with motor enamel spray you
> can also get from a motor shop. Its not the bake on type.
>
> If you ever brake down a DC brush type motor, which I do about every ten
> years, for cleaning, inspecting or replacing the brushes, I use this spray
> on motor enamel to recoat all the field windings, the front of the
> commentator down to the motor shaft and the motor shaft up to the bearing
> surfaces.
>
> When a motor is brand new and never been run, I record the ohm values of the
> motor terminals to the motor frame which should read over 20 meg ohms. The
> commentator windings to the field windings (with the jumpers remove, should
> also read over 20 meg ohms.
>
> As time goes on, the brush dust inside the motor will increase the
> conductance and it may get down to 50 k ohms or less which you may get arc
> over. The its time to clean the motor. Enameling these areas on the
> commentator and motor shaft has increase resistance which allow the motor to
> go over 15 years with no brush replacements.
>
> Roland
>
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