SH Voltage Regulator Update

GordoSD · Jul 29, 2009

Original post is down to page three.
I'm going to go back to square one. Will take the Genny and both non-working V/R in to the magneto shop where it was rebuilt and get a good working matched pair!
I trust the Ammeter as it correctly shows 0 when ignition is off, -2 when ignition on, -5 when lights on (engine not running). Only strange thing is it shows 02 when the engine is running and I can operate the tractor for hours and the battery doesn't run down. And it shows that 25 witht the field point grounded.

Bob M · Jul 29, 2009

Gordo - Sounds to me like the VR relay is stuck in the open (low charge) position. Or at least the ciruit thru the VR points is open somewhere.

Assuming the VR's field resistor is intact, open VR contacts will cause the generator to develop 4 - 5 amps or so at wide open throttle. Deduct 2 amps for the ignition and there's a couple amps "left over" to deflect the ammeter and very slightly charge the battery.

JMOR · Jul 29, 2009

(quoted from post at 14:12:29 07/29/09) Gordo - Sounds to me like the VR relay is stuck in the open (low charge) position. Or at least the ciruit thru the VR points is open somewhere.

Assuming the VR's field resistor is intact, open VR contacts will cause the generator to develop 4 - 5 amps or so at wide open throttle. Deduct 2 amps for the ignition and there's a couple amps "left over" to deflect the ammeter and very slightly charge the battery.

ob, that sounds really correct to me (as if you needed conformation).

If he would insert an ammeter in the wire from gen field to reg field and measure field current and also from gen field to ground (as I suggested in my earlier post), then your analysis would be substantiated.

GordoSD · Jul 29, 2009

Could I just remove the VR cover and see what the points are doing? Close them both "manually" using maybe popsicle stick,and observe the ammeter?

Gordo

JMOR · Jul 29, 2009

(quoted from post at 18:37:25 07/29/09) Could I just remove the VR cover and see what the points are doing? Close them both "manually" using maybe popsicle stick,and observe the ammeter?

Gordo

bsolutely!
When gen starts to output a significant voltage ( above batt voltage) the cut out contacts should close.
When battery voltage is very low, the field contacts stay closed (for max output) & as battery charges up (voltage goes up) & field contacts begin to switch on & off at a rapid rate (like a vibration) and if battery is absolutely fully charged, the field contacts will remain open most of the time,( for minimum charge).

Bob's analysis would yield situation where field contacts are open all the time (hope not putting incorrect words in Bob's mouth).

And when engine is at a very slow idle or stalled, the cut out contacts open, disconnecting gen from battery.

Bob M · Jul 30, 2009

Gordo -

That could work. But keep in mind the VR relay's points move so little (and they move so rapidly when they do) they will appear closed even when they are in fact operating.

Also if the problem is not the VR contacts themselves but instead a break in the circuit to/from the contacts, manually forcing the contacts closed will do nothing.

Bob M

SH Voltage Regulator Update

GordoSD

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Bob M

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JMOR

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GordoSD

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JMOR

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Bob M

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