GS Rectifier/Regulator replace

[bitzz]

Could have only been enhanced if there was a more compact version. The series design with auto disconnect already is a massive improvement over OEM.
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What is "auto disconnect?"

[Rich82GS750TZ]

Came here to ask the same. What do you mean by "auto disconnect? Are you referring to how the series SH 775 effectively shuts down rather than shunting excess voltage?

[jdub6092]

Came here to ask the same. What do you mean by "auto disconnect? Are you referring to how the series SH 775 effectively shuts down rather than shunting excess voltage?

Hey Rich, sorry about the potentially misleading terminology.
My understanding is that the shunt regulator shorts the excess voltage and thus current back through the rectifiers and stator while the series regulator will stop conducting or effectively disconnect above the maximum charging voltage.
So the series R/R only provides the current needed from the source (stator) that is required by the load.
It isn't like a relay that disconnects the source for an extended period or hysteresis window, but switches off at peak stator voltages if load demands are met.
For my bike, with normal load conditions and close to a fully charged battery, this appears to happen somewhere between 4-5k RPM. Above this is where the advantage of the SH775 kicks in.

[Shin-Ken 1074]

Hi jdub6092, does the list you have for a replacement Reg/Rec include one from Yamaha? I found a Yamaha Mosfet Reg/Rec that works on my Suzuki 1982 GSX1100. Installed it today and it is working fine with 14.3 volts on the meter and no heat in the Reg/Rec, after a two hour test ride the Reg/Rec was not even warm, it was as cool as the frame, unlike the 43 year old OEM unit that was getting too hot to touch. The new Yamaha Reg/Rec is much larger than the OEM Suzi unit so spacers were needed to allow the Yammy unit to clear the frame. It is now positioned outboard of the frame however, that is a bonus as the new Reg/Rec has plenty of airflow around it compared to the inboard and sheltered position of the OEM Reg/Rec and my leg doesn't contact the Reg/Rec so its all good.

Reg Rec1 by Max Mutarn, on Flickr


Reg Rec b by Max Mutarn, on Flickr

[Grimly]

I'd be surprised if that Yamaha MOSFET one is a series r/r.

[bitzz]

Yamaha doesn't make that regulator, it's made by Shindengen and you'll find it on a whole bunch of motorcycles, atvs, industrial motors. It is the 'go to" part, and yes it is a MOSFET series device, with a shunt regulator. AFIK there are two Shindenegn part numbers for these, an early one and a later one. The early ones were made in Fukushima and the plant got washed away, and they were harder to get. The later ones have better (faster) MOSFETs.
IIRC the Yamaha is one of the most expensive part numbers, I found the CanAm to be the cheapest. Doesn't matter what name is on the box, they're all the same part.
... and there is more "knock offs" on the market than real ones, so beware of where you get them. I have never seen a "boot leg" one work for more than an hour... BUT there are knock offs that work. I think Rick's electric sells a knock off that he will warranty
A shunt regulator "shunts" or dumps excess power to the frame, or negative battery, they don't turn off the flow. There is no way to stop the rotor from generating electricity when it spins.

[Nessism]

That Yamaha R/R is an FH020AA unit. Shunt type. A quality R/R, but it won't help protect your stator the way a SH775 will. If your stator burns out using it, you may want to consider switching next time.

[Rob S.]

...yes it is a MOSFET series device, with a shunt regulator.

I thought R/Rs were series OR shunt. Can it be both?

[Shin-Ken 1074]

That Yamaha R/R is an FH020AA unit. Shunt type. A quality R/R, but it won't help protect your stator the way a SH775 will. If your stator burns out using it, you may want to consider switching next time.

Thanks for the heads-up Nessism and the advise regarding the SH775. Yes, the one I installed is an FH020AA unit and not the SH775 I should have bought, oops! I'll keep an eye on the volts meter and if it goes over 15 on a ride I'll disconnect one of the yellow stator wires from the harness and hope no damage is done before I get it home. In the past I have been advised to ride with the headlight on hi during the day to help bleed power, maybe that is the reason the original OEM Reg/Rec lasted 43 years?

Cheers.

Reg rec f by Max Mutarn, on Flickr


Reg rec g by Max Mutarn, on Flickr

[Nessism]

Thanks for the heads-up Nessism and the advise regarding the SH775. Yes, the one I installed is an FH020AA unit and not the SH775 I should have bought, oops! I'll keep an eye on the volts meter and if it goes over 15 on a ride I'll disconnect one of the yellow stator wires from the harness and hope no damage is done before I get it home. In the past I have been advised to ride with the headlight on hi during the day to help bleed power, maybe that is the reason the original OEM Reg/Rec lasted 43 years?

Cheers.

43 years with a shunt R/R. I wouldn't worry a whole lot about the situation now! I'd run it, but keep a search open for a SH775. They both use the same connector, so an easy swap.

[bitzz]

I thought R/Rs were series OR shunt. Can it be both?

Shunt describes the function of the regulator. It "shunts" excess power. Permanent magnet rotor alternators, like on most modern motorcycles, all have a shunt regulator. With a permanent magnet alternator the only thing regulating stator AC output is the RPM.
The "usual" type regulator (like you find on a car) varies the voltage, increasing or decreasing the magnetism, in the rotor to regulate AC output of the stator. (Sorry I can't remember what you would call this setup... "switching" regulator maybe... and there is at least 3 common types of these setups)
So if the alternator doesn't have brushes, it probably has a shunt regulator


Series describes the circuit. A series reg has the regulator circuit in series with the power "flow". A parallel regulator the regulating circuit is parallel to, or beside, the "flow". A series reg has a lot less wiring in it, so it runs cooler.

https://www.google.ca/search?q=electrical+difference+of+series+and+parallel+circuits&newwindow=1&source=hp&iflsig=ACkRmUkAAAAAaCIP_bsRzW4TEcIpnFTGyLB7u1iyT8NF&oq=electrical+difference+of+series+and+pa

The MOSFET part is the diodes in the rectifier. Mosfet diodes are more efficient than regular diodes. They're much faster switching and require a LOT less power to run (by like a factor of 5), meaning a lot less heat. Heat is a major cause of reg/rec failure, when heat goes up, resistance goes up, which causes more heat and more resistance till the smoke escapes

[Grimly]

nnnnnnnnnnnnnnnnnnnnnnnn

[Shin-Ken 1074]

43 years with a shunt R/R. I wouldn't worry a whole lot about the situation now! I'd run it, but keep a search open for a SH775. They both use the same connector, so an easy swap.

Thanks, good to know it is a plug and play swap for the SH775 now that I have the wiring and connectors in place.