DC motor Control questions

[quicksandfarmer]

Why not try and accomplish the flows and pressures you want on the fluid side.
Restricting the flow on a centrifugal pump reduces the load since there is no flow.
A globe valve on the output would give you a reasonable throttling control. Don't use a ball valve as fine tuning it is difficult.
You can also tee off some of the output and send it back to the reservoir using a valve to control how much .
Dave M7040

I think Dave is on the right track. Does it have to be DC? Does it need to be a special pump or will a water pump work? You could do this with a normal shallow well pump with a pressure tank and a pressure switch. Just like house plumbing, a valve moderates the flow. Pump turns on and off with the pressure switch. Easy-peasey.

 

[blakester]

So I will be pumping Grape must. Was thinking about peristaltic as the pump type as yes it has to be food grade. Since I have to compress the tube I would expect to have more torque requirements. I believe if I go with this pump type that I wont be able to do it on the fluid side as it will want to push out a pre-determined amount of fluid. So high viscosity, and tube compression, hence the 5hp consideration. I'll check out the VFD more throughly tonight as an option.
'll

 

[blakester]

If I do go with FVD, can i use any sigle phase AC motor with it?

 

[Mendonsy]

If I do go with FVD, can i use any sigle phase AC motor with it?

No, it will have to be a 3 phase motor.

 

[shiftyguy]

If you can only supply single phase power to the input of the VFD check the manufacturer's specs
to make sure it will allow you to run it on single phase. You will also need to derate a single phase
input drive. You may need to get a 7.5 or 10 H.P. drive to run your 5 H.P. motor

 

[LD1]

If you can only supply single phase power to the input of the VFD check the manufacturer's specs
to make sure it will allow you to run it on single phase. You will also need to derate a single phase
input drive. You may need to get a 7.5 or 10 H.P. drive to run your 5 H.P. motor

If the drive is not rated for single phase, it can still work with single phase input but you do have to derate.

If the drive is dual rated for both 1/3 phase (most of the smaller ones under 3hp are), you dont need to derate.

 

[LD1]

If you can only supply single phase power to the input of the VFD check the manufacturer's specs
to make sure it will allow you to run it on single phase. You will also need to derate a single phase
input drive. You may need to get a 7.5 or 10 H.P. drive to run your 5 H.P. motor

If the drive is not rated for single phase, it can still work with single phase input but you do have to derate.

If the drive is dual rated for both 1/3 phase (most of the smaller ones under 3hp are), you dont need to derate.

 

[Redneck in training]

If the drive is not rated for single phase, it can still work with single phase input but you do have to derate.

If the drive is dual rated for both 1/3 phase (most of the smaller ones under 3hp are), you dont need to derate.

Can you run a single phase motor using two phases (without capacitor)?

 

[LD1]

I don't really understand.

Are you asking if you have three phase, if you can run a single phase motor off just two legs, the answer is no.

 

[arlen4720]

I don't really understand.

Are you asking if you have three phase, if you can run a single phase motor off just two legs, the answer is no.

If you have a 3 phase system, say 208/120 volt, you can certainly run a single phase 208 volt motor off 2 of the legs.

A vfd would work pretty good for the OP, but given that he needs less than 1 hp, a DC motor and speed control from Grainger might be cheaper.