Stator wires going to Rectifier heating up

[Bowtie Man]

Hey,
Just wondering if any of you out there have had troubles with the wires coming from the stator heating up. After a run on the dyno ours are getting upwards of 140F. If so could you tell me what was happening, or how you fixed it.
Thanks

[Bowtie Man]

Hey,
Just wondering if any of you out there have had troubles with the wires coming from the stator heating up. After a run on the dyno ours are getting upwards of 140F. If so could you tell me what was happening, or how you fixed it.
Thanks

[GTmule]

We burned up a rectifier, on the test stand......any ideas?

[Colin]

what engine are you guys running, and how much current are you trying to get out of the system

[3A]

We're running GSXR, and should not be pulling more than 8A steady. (all we have on the dyno is PE ECU and a fuel pump). We should be able to squeeze 25A out of the system, thus we're well below the rated limit. Also, voltage readings with engine running are over 14V, thus rectifier is doing its job. Wires on the output of the rectifier are ok. Battery is brand new.

[Agent4573]

Bowtie man, try putting some dielectric grease on your rectifier and see if the temp comes down.

[GTmule]

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by 3A:
We're running GSXR, and should not be pulling more than 8A steady. (all we have on the dyno is PE ECU and a fuel pump). We should be able to squeeze 25A out of the system, thus we're well below the rated limit. Also, voltage readings with engine running are over 14V, thus rectifier is doing its job. Wires on the output of the rectifier are ok. Battery is brand new. </div></BLOCKQUOTE>

Same deal, but with an F3, PE ecu, and a fuel pump (and some superficial stuff, a tach and a h20 temp gage). The rectifier itself just got hot as hell, then burned up....?

[BryanH]

I found a guy who is a bit of an authority on bike alternator/rectifier systems, he supplies race teams around the world with bespoke systems. I will run this situation past him in the morning (13hours)

[aniLD]

We have had the same problem on a GSXR with a motec on the dyno, it actually melted the insulation on the wires so we just rewired it and are monitoring it. It still gets hot so im interested in a solution also.

[Akos]

I've had similar problembs with an F4.

The rectifiers will get hot. If the rectifier doesn't have any finns, it needs to be mounted on a heat sink. It also needs some airflow across it, as small PC power supply fan should work well for dynoing.

The stock connector on the alternator usually sucks. This causes the wires to get really hot near the conector and melt. Replace the connector with a heavy duty one (ie Deutsch DTP) and you won't have problems. Also don't try to skimp on the wire sizes.

Cheers,

Akos

[Alexandre D.]

Our rectifier gets real hot if the car is not moving but as soon as the heat sink has some air, the temp is ok.
I'm impressed how reliable the rectifier is. The rectifier was connected the wrong way and it didn't melt.
Buy a rectifier with a heatsink and make sure it has some fresh air.
We draw much more power than a stock F4 would and it still runs fine.

[BryanH]

OK here is the deal,
All the Jap. rectifiers are manafactured by one company and are internally the same in operation.
( Except Honda which use hard ceramic based units, early ones are unreliable but have superceded many times,latest one is very small & good.)
All of these rectifiers short the stator wires together at a set rpm point (high in the range but don't know exact point) to stop excess output and reduce drag. On RMIT-04 it was worth a few hp when they went to this style of reg. with custom 2 phase stator.
I'm guessing you are all holding the engine at high rpm on the dyno for extended periods, and the shorted out stator will get hot in this situation. Simplest fix is to cut 1 of the 3 wires coming off the stator, Dropping output by approx 1/3.
This was a Kawasaki factory fix on one of their quads that kept buring out rectifiers!
You could dyno the engine with the rect. disconnected and use a battery charger to keep voltage constant
Bryan H.

[Charlie]

Well we have run a Honda F4 and F4i reg at extended operation at very high RPM with no problems. You must use a heat sink if you want your regulator to not melt though!! That is unless it does not have an integrated one. Keep cool air over the sink and you should not have melting problems.