Selecting a 3 phase motor for RPC set up. Which HP?

RRT

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I have a 1 HP 3 phase power hacksaw. I have several 3 phase motors to choose from. 1/2 hp to 3 HP. Maybe higher if I dig some more. Is it best to match HP? Thanks.
 
Everything I've heard about RPCs says that you lose some capacity from the supply motor. That would suggest that you use the 3 hp to generate 3-phase for the 1 hp. They both need to be the same voltage and frequency ratings.
 
I have a 1 HP 3 phase power hacksaw. I have several 3 phase motors to choose from. 1/2 hp to 3 HP. Maybe higher if I dig some more. Is it best to match HP? Thanks.

RRT,
is your 1hp motor failing? or are you wanting to try to do a motor swap for some other reason?
On a direct 3Ph setup you can put what ever you like since the motor is 3Ph and the incoming line is 3Ph.
example: if you had a 220 setup. the 220 doesn't care what you put on it and neither will the 3Ph. however as you go up in Hp
so will the amperage draw. a supply cable or breaker change might be in order.

However if your using a VDF driver. then first I would consult the manual for your particular device. but in general I would say
its ok to go =< the rated Hp for such device but never more than.

Then you have the equipment. I would also say if the equipment was engineered correctly. the motor that ships with it
should be the telltale for the targeted/desirable Hp.

best!
Sam
 
RRT,
is your 1hp motor failing? or are you wanting to try to do a motor swap for some other reason?
On a direct 3Ph setup you can put what ever you like since the motor is 3Ph and the incoming line is 3Ph.
example: if you had a 220 setup. the 220 doesn't care what you put on it and neither will the 3Ph. however as you go up in Hp
so will the amperage draw. a supply cable or breaker change might be in order.

However if your using a VDF driver. then first I would consult the manual for your particular device. but in general I would say
its ok to go =< the rated Hp for such device but never more than.

Then you have the equipment. I would also say if the equipment was engineered correctly. the motor that ships with it
should be the telltale for the targeted/desirable Hp.

best!
Sam

Sorry Sam I should have been clearer. I am not changing the motor on the power hack. I was trying to determine the best HP for the extra 3 phase motor used in converting single phase 220 to 3 phase for the power hack. Oh, and I would love to have a manual for that old monster.
Thanks
 
I have a 1 HP 3 phase power hacksaw. I have several 3 phase motors to choose from. 1/2 hp to 3 HP. Maybe higher if I dig some more. Is it best to match HP? Thanks.

Here you have "several" 3 phase motors...

RRT;60793 I am not changing the motor on the power hack. I was trying to determine the best HP for the extra 3 phase motor used in converting single phase 220 to 3 phase for the power hack. Oh said:
RRT,

Sorry, Im a little confused... you also say your "not changing the motor".

Sounds to me like your considering/wanting to change out the PH(power hack) motor for perhaps a better setup using one of the motors you already have?

but all your motors are 3 phase?

So you will need either 3Ph source , or a Phase convertor or a VFD.

and then how to choose? which motor.

If your considering a VFD. the VFD chosen will clearly state the voltages/amperage conversions for 3Ph motor in question.
Im not an EE but i think in general it doubles or gets cut in half depending on which way you look at it.
Also, if you have the 220 source thats what I would stick with. but you could even drop down to 110/115 as a source. if you went with the 1Hp.
after that I think 220 will be the standard for any motors >1hp. (in general). also I know theirs some loss in amperages when converting. But Im pretty sure
the VFD eats up the losses on the source side. not the motor side so 1hp=1Hp, and 2hp=2hp. so no loss on the motor side.

So I think its safe to say that a 1Hp 3phase setup with 3 phase as its source is the same as a 1hp 3phase using a VFD with 220 as a source is pretty much the same result 1Hp.

I hope I hit the target!


Sam
 
Use the largest one you can get-in this case the 3HP one. That way you can use the RPC for future purchases as well. There is no need to "match" the RPC to the tool it powers, as long as the RPC is rated higher you will be fine.
 
Here you have "several" 3 phase motors...



RRT,

Sorry, Im a little confused... you also say your "not changing the motor".

Sounds to me like your considering/wanting to change out the PH(power hack) motor for perhaps a better setup using one of the motors you already have?

but all your motors are 3 phase?

So you will need either 3Ph source , or a Phase convertor or a VFD.

and then how to choose? which motor.

If your considering a VFD. the VFD chosen will clearly state the voltages/amperage conversions for 3Ph motor in question.
Im not an EE but i think in general it doubles or gets cut in half depending on which way you look at it.
Also, if you have the 220 source thats what I would stick with. but you could even drop down to 110/115 as a source. if you went with the 1Hp.
after that I think 220 will be the standard for any motors >1hp. (in general). also I know theirs some loss in amperages when converting. But Im pretty sure
the VFD eats up the losses on the source side. not the motor side so 1hp=1Hp, and 2hp=2hp. so no loss on the motor side.

So I think its safe to say that a 1Hp 3phase setup with 3 phase as its source is the same as a 1hp 3phase using a VFD with 220 as a source is pretty much the same result 1Hp.

I hope I hit the target!


Sam








Sam, he wants to build a RPC...and is asking what motor to use.
 
I'm pretty sure the ratio is 1.5 times the largest motor that you planninng on running. Example: 5hp machine motor x 1.5= 7.5 hp phase converter. In you're case, 3hp phase converter would be plenty to run the saw but it want run anything over 2hp. Hope this helps.
 
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