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FW: (ET) E-15 Reverse relay Arcing

Thanks for all the feedback. One other question. I don't think the brake 
switch is working, could this be part of the problem?
Also I'll tell my wife to make sure she stops completely before going into 
reverse. She thought I was having too much fun mowing with the Elec-trak. 
She has been mowing ever since. That was 18 years ago. Now I mostly keep 
it running.
                                                        
                                                                Steve

-----Original Message-----
From:   Chris Zach [mailto:czach computer org] 
Sent:   Thursday, May 01, 2003 9:50 PM
To:     Steve Caplan
Cc:     ET Discussion List (E-mail) (E-mail)
Subject:        Re: (ET) E-15 Reverse relay Arcing

The E15 is a bit different than the E20. On the E20, reverse was made by 
using 4 contactors to reverse the polarity on the armature. They were in 
a push-pull arrangement so a failure couldn't blow the armature sky 
high. As a result, in reverse the tractor had less torque (due to the 
fact that the field was weakened since technically it is a compound-ish 
motor)
On the E15, reverse is controlled by using a single relay to reverse 
polarity on the field. A lot cheaper, but if the tractor is moving 
forward *at all* when you toss it into reverse you are going to get a 
relay-melting spark.

There might be a varistor that goes across the relay to absorb the 
sparks, or a capacitor. If so I'd bet it's blown.

Chris

Steve Caplan wrote:
> Hi group,
>       My E15 reverse relay arcs alot. I have burnt up two relays. They 
> were both used. Is this because they were old and probably not adjusted 
> properly or is there some other cause I should look for?  Can I expect 
> it to work if I order new relays from Bill? Can I expect to find them at 
> a local large electronics supply house?
>                                                       Thanks in advance 
> for your help,
>                                                       Steve
>                                                       Baltimore County, 
> Maryland
> 
> 
> 
>