TRF Forums
https://www.trf.org.uk/forum/

Main fuse blowing, is it a voltage regultor?
https://www.trf.org.uk/forum/viewtopic.php?f=36&t=23838
Page 5 of 6

Author:  mancchair [ Wed Aug 02, 2017 7:29 am ]
Post subject:  Re: Main fuse blowing, is it a voltage regultor?

How would a short cause the voltage to almost double ?

Author:  Rusty [ Wed Aug 02, 2017 9:23 am ]
Post subject:  Re: Main fuse blowing, is it a voltage regultor?

Perhaps a short going from the input wire of the reg/rec to it's output?, effectively bypassing the reg/rec?
I assume the input and output wires are bundled together at some point

Allways hard to fault find from a distance.

Author:  Bill_Mc [ Wed Aug 02, 2017 10:36 am ]
Post subject:  Re: Main fuse blowing, is it a voltage regultor?

.

Author:  smokinrider [ Wed Aug 02, 2017 11:54 am ]
Post subject:  Re: Main fuse blowing, is it a voltage regultor?

Although the ac voltage is unregulated it surely cannot generate more that the windings permit so a massive spike from the generator part is unlikely. The chance of a new regulator/rectifier failing immediately is possible but it is unlikely.

Could the real cause be the trailtec aftermarket speedo? Maybe eliminate this by removing it from the equation and going for a ride.

Have we established if the fuse blows by just revving the bike or does it only blow when the bike is ridden. (Vibration, bumps, jolts, steering lock) all being a possible cause of an intermittent short.

Could a minor(single strand of wire) short cause a load, which is enough to cause the reg/rec to increase its output enough to blow a fuse?

Has the earth strap been removed and cleaned and all engine bolts checked to ensure a proper earth is made.

Too many unknowns and variables here to accurately diagnose anything.





Sent from my iPhone using Tapatalk

Author:  mancchair [ Wed Aug 02, 2017 12:15 pm ]
Post subject:  Re: Main fuse blowing, is it a voltage regultor?

Bill_Mc wrote:
I posted the wiring diagram earlier in the string.
two wires from the alternator are unregulated AC voltage, the rectifier regulator changes them to DC and regulates the voltage output.
If the high voltage is not measured with a reliable meter I would question it.
Fuses blow on amperage drawn rather than high voltage, I would double check the two red output wires from the fuse for short circuit to ground, most likely rubbed somewhere.


If the volts go up the amps go up :)

Author:  mancchair [ Wed Aug 02, 2017 12:21 pm ]
Post subject:  Re: Main fuse blowing, is it a voltage regultor?

Although the ac voltage is unregulated it surely cannot generate more that the windings permit so a massive spike from the generator part is unlikely. The chance of a new regulator/rectifier failing immediately is possible but it is unlikely.

It can if there is debris in there shorting the windings, unlikely but this happened on one of mine and cooked the ecu and reg/rec,

I also said after your checks I would suspect the generator :)

Author:  Mitso [ Thu Aug 03, 2017 5:28 pm ]
Post subject:  Re: Main fuse blowing, is it a voltage regultor?

I was just about to take it to an electrical guy when I noticed that pulling on the handbrake made the lights in the Trailtech flicker, I started it up with a new fuse in and rode it around a field and found that on using the hand brake the voltage would drop to about 9v from 13.4v. Every time I pulled on the lever the voltage would drop and no brake light coming on, I pressed the foot brake which brought the brake light on and it appeared to reset the hand brake which then worked correctly - no v drop and brake light on.

It didn't blow the fuse but maybe it would have done eventually.

The new rectifier appears to be ok as does the old rectifier as I swopped them around whilst the bike was working and not popping the fuse.

I am thinking there is a short in the brake wires somewhere which must be intermittent, I am now going to replace the wiring and see what happens.

The high voltage only happens after the main fuse has popped for some reason, it then goes between 15v-20v.

Author:  mancchair [ Thu Aug 03, 2017 5:58 pm ]
Post subject:  Re: Main fuse blowing, is it a voltage regultor?

Most likely but also check the brake light lamp/holder and wiring all the way ;)

The high voltage reading could be a back feed from the trailtech, as smokinrider mentioned this could be causing problems :)

Author:  Bill_Mc [ Thu Aug 03, 2017 8:51 pm ]
Post subject:  Re: Main fuse blowing, is it a voltage regultor?

/

Author:  smokinrider [ Thu Aug 03, 2017 10:54 pm ]
Post subject:  Re: Main fuse blowing, is it a voltage regultor?

Have you not cleaned and inspected and checked all wires and unplugged and cleaned all connectors and bulbs.

I thought this was the first thing you were advised. You'll be chasing this fault forever if it's just a frayed wire or bad earth if you don't do the basics first.

I suspect now it's a corroded spring or loose wire in the rear light bulb holder! As from what you've just said it's sounds more and more like a bad earth.


Sent from my iPhone using Tapatalk

Page 5 of 6 All times are UTC [ DST ]
Powered by phpBB © 2000, 2002, 2005, 2007 phpBB Group
http://www.phpbb.com/