The Ford Barn

Lawrie · 11-01-2021, 01:39 AM

Amy one know what Hp the generator uses.
I have a generator and starter tester that I have just got, with a burned out electric motor and Im thinking of putting a modern VSD and electric motor on to drive it but need the hp required so I can size up a motor and VSD.
JM 35??
Thanks Lawrie

koates · 11-01-2021, 02:16 AM

Hi Lawrie, I have a generator/alternator starter test bench which has a variable speed forward and reverse 3 HP electric motor which does most automotive car and light truck equipment. Look up "DURST"automotive electrical test equipment in Sydney. Regards, Kevin.

Lawrie · 11-01-2021, 05:19 AM

Kevin, thats what I have but with a buggered armature, would you know where to get one, they said to rewind ist would be VERY expensive.
I have sent them an e/mail so will see what they come back with.
Lawrie

koates · 11-01-2021, 05:37 AM

Lawrie, those big 3 HP Durst armatures are a complicated winding so are costly but they are the best to ask. While I have you do you know anyone who would have an original fairly complete 1932 V8 engine. Has to be all correct 1932. Regards, Kevin.

Lawrie · 11-01-2021, 06:32 AM

No Kevin , sorry ,
Lawrie

Frank Miller · 11-01-2021, 06:56 AM

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Hope this helps. 35 amps at 6 volts equals 210 watts. 1 hp is 746 watts. I'm thinking a fractional size 1/2 to 3/4 hp motor will be plenty.

rotorwrench · 11-01-2021, 08:54 AM

A generator is sort of a variable load component. If it is called to put out near it's maximum amperage capacity then the amount of torque it takes to turn it increases a good bit. If it's pared with a normal system and a good storage battery then it won't take all that much torque to turn it. When a battery is back to fully charged state, all the generator has to do is power the electrical loads that are needed for the engine to run. The battery acts as an accumulator to balance the load needs.

The power it takes to turn a generator in watts with an electric motor is likely a fair bit more than what the generator will put out so it would be a losing battle in continuous operation.

I finally figured out what you were looking for. A 1/2 HP AC motor should be fine if you get a shaft size and mounting set up that works for the old machine. Over here in the US we can go to Grainger supply and find motor set ups & rpm controls that can generally be made to work but folks outside the US likely have to really poke around for sources on stuff like this. The VFD should eleminate the capacitor start so there may be motors set up to work without. A larger motor would strain less but they start getting pretty big over 3/4 HP

On aircraft starter generators, we only had to turn them to seat the brushes. On generators you don't have to load them up all that much to test the output unless it's a real big generator.

Lawrie · 11-01-2021, 03:32 PM

Thank you Frank, thats the into I needed,
I want to price up a modern variable speed drive and electric motor and needed the HP to size the motor,
this is if I cant get a replacement armature for the motor on the tester I have,
Lawrie

Bob C · 11-01-2021, 04:26 PM

For an alternator this link says it takes about 1HP for every 25 amps.
https://findanyanswer.com/how-many-h...-an-alternator

11-01-2021, 01:39 AM	#1
Lawrie Senior Member Join Date: May 2010 Location: Qld, Australia Posts: 4,218	generator HP Amy one know what Hp the generator uses. I have a generator and starter tester that I have just got, with a burned out electric motor and Im thinking of putting a modern VSD and electric motor on to drive it but need the hp required so I can size up a motor and VSD. JM 35?? Thanks Lawrie

11-01-2021, 02:16 AM	#2
koates Senior Member Join Date: May 2010 Location: Melbourne Australia. Posts: 2,079	Re: generator HP Hi Lawrie, I have a generator/alternator starter test bench which has a variable speed forward and reverse 3 HP electric motor which does most automotive car and light truck equipment. Look up "DURST"automotive electrical test equipment in Sydney. Regards, Kevin.

11-01-2021, 05:19 AM	#3
Lawrie Senior Member Join Date: May 2010 Location: Qld, Australia Posts: 4,218	Re: generator HP Kevin, thats what I have but with a buggered armature, would you know where to get one, they said to rewind ist would be VERY expensive. I have sent them an e/mail so will see what they come back with. Lawrie

11-01-2021, 05:37 AM	#4
koates Senior Member Join Date: May 2010 Location: Melbourne Australia. Posts: 2,079	Re: generator HP Lawrie, those big 3 HP Durst armatures are a complicated winding so are costly but they are the best to ask. While I have you do you know anyone who would have an original fairly complete 1932 V8 engine. Has to be all correct 1932. Regards, Kevin.

11-01-2021, 06:32 AM	#5
Lawrie Senior Member Join Date: May 2010 Location: Qld, Australia Posts: 4,218	Re: generator HP No Kevin , sorry , Lawrie

11-01-2021, 06:56 AM	#6
Frank Miller Senior Member Join Date: May 2010 Location: Auburn, MA Posts: 2,106	Re: generator HP Sponsored Links (Register now to hide all advertisements) Hope this helps. 35 amps at 6 volts equals 210 watts. 1 hp is 746 watts. I'm thinking a fractional size 1/2 to 3/4 hp motor will be plenty. __________________ “The technique of infamy is to start two lies at once and get people arguing heatedly over which is true.” ~ Ezra Pound

11-01-2021, 08:54 AM	#7
rotorwrench Senior Member Join Date: Jun 2010 Location: San Antonio, Texas Posts: 16,440	Re: generator HP A generator is sort of a variable load component. If it is called to put out near it's maximum amperage capacity then the amount of torque it takes to turn it increases a good bit. If it's pared with a normal system and a good storage battery then it won't take all that much torque to turn it. When a battery is back to fully charged state, all the generator has to do is power the electrical loads that are needed for the engine to run. The battery acts as an accumulator to balance the load needs. The power it takes to turn a generator in watts with an electric motor is likely a fair bit more than what the generator will put out so it would be a losing battle in continuous operation. I finally figured out what you were looking for. A 1/2 HP AC motor should be fine if you get a shaft size and mounting set up that works for the old machine. Over here in the US we can go to Grainger supply and find motor set ups & rpm controls that can generally be made to work but folks outside the US likely have to really poke around for sources on stuff like this. The VFD should eleminate the capacitor start so there may be motors set up to work without. A larger motor would strain less but they start getting pretty big over 3/4 HP On aircraft starter generators, we only had to turn them to seat the brushes. On generators you don't have to load them up all that much to test the output unless it's a real big generator. Last edited by rotorwrench; 11-01-2021 at 04:44 PM. Reason: Didn't understand the question

11-01-2021, 03:32 PM	#8
Lawrie Senior Member Join Date: May 2010 Location: Qld, Australia Posts: 4,218	Re: generator HP Thank you Frank, thats the into I needed, I want to price up a modern variable speed drive and electric motor and needed the HP to size the motor, this is if I cant get a replacement armature for the motor on the tester I have, Lawrie

11-01-2021, 04:26 PM	#9
Bob C Senior Member Join Date: May 2010 Location: So Cal Posts: 8,755	Re: generator HP For an alternator this link says it takes about 1HP for every 25 amps. https://findanyanswer.com/how-many-h...-an-alternator