late 60s bigtwin generator RPM

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late 60s bigtwin generator RPM

#1

Post by panhead_kicker »

I'd like to set up a test bench for my 65A generator, spinning it with a 110v induction motor via pulleys and belt.
Does anyone know the calculation/relationship to go from bike RPM to actual generator RPM?
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Re: late 60s bigtwin generator RPM

#2

Post by flat38 »

I don't know about a pan but I recently did this calculation on my U. I can't imagine they changed it much. It worked out to 2200 engine RPM was approximately equal to 3300 generator RPM. The reason I say approximately is that I hooked up my generator to an electric motor with a direct drive. The motor is very old and the ID plate was long gone so I used a mechanical tach hooked to the motor shaft to approximate RPM.
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Re: late 60s bigtwin generator RPM

#3

Post by Larry »

I built this tester to do exactly what you intend. A 1725 rpm motor drives a 4" pulley. The generator is driven by a 2" pulley. The generator turns at approximately 3450 rpm. If a generator tests good on this device, it will perform properly in service.[attachment=1]tester1b.JPG[/attachment][attachment=0]teater2b.JPG[/attachment]
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Re: late 60s bigtwin generator RPM

#4

Post by panhead_kicker »

Larry wrote: Mon Aug 22, 2022 12:02 am I built this tester to do exactly what you intend. A 1725 rpm motor drives a 4" pulley. The generator is driven by a 2" pulley. The generator turns at approximately 3450 rpm. If a generator tests good on this device, it will perform properly in service.tester1b.JPGteater2b.JPG
Thats awesome Larry! A bit more elaborate than what i had in mind , but yeah. Plus the ability to chek\adjust regulator . What hp is your motor ?
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Re: late 60s bigtwin generator RPM

#5

Post by Larry »

1/3 hp
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Re: late 60s bigtwin generator RPM

#6

Post by panhead_kicker »

Larry wrote: Mon Aug 22, 2022 9:47 pm1/3 hp
Did you simply go with what you had, and it worked? I have a 1/6 hp motor, wondering if it's got the torque needed. Don't have the pulleys yet.
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Re: late 60s bigtwin generator RPM

#7

Post by Larry »

It's easy to turn the generator, but application of a load can cause the motor to stall.
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Re: late 60s bigtwin generator RPM

#8

Post by panhead_kicker »

Larry wrote: Tue Aug 23, 2022 3:17 pm It's easy to turn the generator, but application of a load can cause the motor to stall.
I’m planning on welding a generator gear to a pulley . How did you handle it?
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Re: late 60s bigtwin generator RPM

#9

Post by Larry »

I made a threaded adapter that replaces the nut.
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Re: late 60s bigtwin generator RPM

#10

Post by RooDog »

Somewhere I remember seeing a fellow testing a genny by simply running a V-belt on the genny's drive gear. Since this is not a long term application,and simply for test purposes, it seemed to work for him.
Remember, this is only a test. Your results may vary....
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Re: late 60s bigtwin generator RPM

#11

Post by Buddhahoodvatoloco »

[media]Love it, "...this is only a test. Your results may vary." Like the belt coming lose and scaring the bejusus out you. Como decien en los estados pinchi unidos, "Where there's a will theres a way. Especially now with the internet........ :lol: [/media]
RooDog wrote: Tue Aug 30, 2022 5:25 pm Somewhere I remember seeing a fellow testing a genny by simply running a V-belt on the genny's drive gear. Since this is not a long term application,and simply for test purposes, it seemed to work for him.
Remember, this is only a test. Your results may vary....
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Re: late 60s bigtwin generator RPM

#12

Post by RUBONE »

The original generator testers supplied by Weidenhoff had a split pulley that clamped over the top of the gear to operate at the correct RPM range.
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