120 vac motor speed controller

kamaroman68

Member
K
Join Date
Apr 2014
Location
Niagara Falls
Posts
36
Guys its been awhile since Ive posted on the forum...

Im looking for a device to control motor speed of a 120vac single phase pump using 4- 20ma control from a plc. Anyone ever come across such a device. Thanks for looking!

Chris
 
Unfortunately that particular drive is 3 phase out...

Looking for a device which uses 120vac single phase power, to vary the speed of a 120vac single phase pump motor. Thanks again
 
kamaroman68 said:
Unfortunately that particular drive is 3 phase out...

Looking for a device which uses 120vac single phase power, to vary the speed of a 120vac single phase pump motor. Thanks again
Click to expand...

There are variators to regulate small single-phase motors, but in general they have a low efficiency and the motor gets very hot.

You should consider changing the motor to a three phase one and use a variator as suggested. It would be a much more reilable solution.
 
Is this a new application or existing?
There are Triac Single phase controllers out there. However, they only work with certain motor types, and usually only fractional horsepower ones. I have one on a small drill press at home. I have never seen one that accepted a 4-20mA signal.

If it is a new application, depending on the flow rate required, there are a lot of small dosing pumps on the market that will take a 4-20 signal, most vary the stroke of the pump.
 
What is it doing? if your doing some sort of motion maybe swap with a stepper, if your running a conveyor type maybe a DC would be a better option?
 
Hey guys thanks for the replies... Its for a pond pump. The owner has a plc controlled house. He's looking to control the speed of the pump. He currently has 2 pumps in the skimmer housing, one "big" pump and one "small" pump. He's activating which pump runs using a simple relay. The problem with this setup is the use of the check valves. The check valves get gummed up often and then there is little to no flow when the alternate pump is selected. I was hoping to get rid of the small pump and all check valves and just control the speed of the "big" pump. Hope this makes sense..... Thanks again guys
 
I have used one of the Invertek drives for a single phase application where it was impractical to get to the blower motor. It didn't work well, but was somewhat functional. I would not recommend it except for very specific situations. There are limits to the type of single phase motors it can work with. I would recommend upgrading the pump to 3 phase.

Here's a link to the drive we used, and there was nothing wrong with their hardware, just limitations with what is possible with that type of motor.

https://www.invertekdrives.com/variable-frequency-drives/optidrive-e3
 
A few things most single phase motors can not be used with a VFD of any king
Capacter Start, Startee winding witha switch are all fixed speeed
the most vfd may rate them at 120vac single phase in but the output is also only 120vac 3 phase they require a 3 phase motor but will only give you 1/2 the rated HP out
Yor best option is Yaskawa they have a 120VAC single phase input that will give you the full 230VAC 3 phase out. The has a voltage doubler built
if you need a verable speed motor them you have to change to a3 phase motor or use a DC motor with a DC drive
 
I like Ken's thought. Are the two existing pumps in physically different locations? If you have room for the small pump and motor with a check valve I would think you would have room for a valve.

Keith
 
I think recirculation is a good idea, but as long as a minimum flow is maintained since if close the entire flow were recirculated, the fluid could heat up.
 
There are a few single phase input, 3 phase output drives that work fairly well. I’ve use Automation Direct drives. You will still need to change the motor, but if your supply is limited to single phase this could be an option.
 

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