Soft Start vs Hard Start for Compressors/Motors?

[tookielee]

A Hard Start Kit is essentially a plug-and-play Start Capacitor and Start Relay all in one. This simply plugs on to the existing Run Capacitor with two wires,
and takes a few minutes to install with just basic tools. If there is already some sort of "start assist" device installed, this gets removed and discarded.
A Soft Start is essentially a Hard Start Kit on steroids. It too contains a Start Capacitor and some type of Start Relay, electronic or otherwise, but also
employs comprehensive electronics with sophisticated algorithms that sense and record multiple aspects of the start routine, and which constantly adjust
the settings in order to produce the best result.

 

[Industrial Toys]

A soft start is usually a VFD. Variable Frequency Drive.

 

[grsthegreat]

A soft start is usually a VFD. Variable Frequency Drive.

ya, but these are simply terms. We used to call all VFD’s soft starts years ago.....then transitioned to callimg them Variable freq drives.....sounded more sophisticated so we could charge more.

 

[Popgadget]

How does a VFD work with single phase motors?
I’ve used them on 3 phase motors and they work great. I actually use one as a speed control on my Bridgeport, and as a bonus it’s single phase in, 3 phase out, replacing a big old rotary phase converter.

 

[grsthegreat]

I have seen VFD’s installed on single phase motors in the past, but you have to disable certain functions in the controller for them to work. Im really not sure why someone would bother with single phase motors though. I believe the motor needs to be rewound in order for a vfd to operate a single phase motor. So you have to pay more for specially wound motor just to us the speed controls. Where i saw them was in a printing shop operation that did not have 3 phase power. This was some years ago. I had to contact the manufacturer before i even attempted the install. It thru me, but it did work when all was said and done.

 

[Industrial Toys]

I would have thought that pumps and stuff that run on a Soft Start would be three phase, since many VFDs are great at making 3 phase out of single phase if derated.

 

[grsthegreat]

I would have thought that pumps and stuff that run on a Soft Start would be three phase, since many VFDs are great at making 3 phase out of single phase if derated.

i have hooked up alot of 3 phase deep well pumps onto landscape waterfalls for rich folk up here for years. they build $100,000 landscape projects with waterfalls and need the pumps to move the volume of water. we install a deep water 3 phase pump motor onto a single phase powered VFD unit. its nice to be rich. one of the last ones i hooked up had 800 amps to the house and we had to bring in another 200 amp panel to run the landscape system. all the lighting, xmas tree outlets at nearly every large tree, fountains and pond pumps everywheres.

 

[Travelover]

With many of us wanting to do more with smaller generators or limited power I'm hoping those in the know will post the good and bad along with pitfalls to avoid when sizing and buying.

It almost seems like magic simply adding a small electronic gizmo let's smaller generators do the heavy start up often required for motors.

Aside from cost is there a downside to limiting starting amps?

Do Hard Start and Soft Start kits perform the same function?

Goodman sells a Hard Start kit for $60... Some of the Soft Start or Easy Start kits sold to RV trade sell for $300.

Are the dozens of products offered about the same or do some cut corners?

I installed an Easy Start on my camper AC and it works really sweet. Previously the 2000 watt Honda inverter generator struggled when the head pressure got higher when it got hot, so you couldn't leave it on eco mode and have it restart the AC without struggling. Now I just leave it on eco mode and it starts the compressor no problem. Also when the AC starts there is no THUNK! when the compressor kicks in, just a smooth ramp up. The EasyStart is like driving a manual transmission vehicle and slipping the clutch a little as you take off vs just popping the clutch. It is completely different animal than hard start capacitors that have been used for years.

The EasyStart 364 is about $300, but they sell just the circuit board (model 366) for about a hundred bucks less. You do have to supply your own new capacitor with the 366, for about ten bucks. Sure beats buying a second Honda inverter generator and linking them together just so you have enough starting power for the initial AC surge.

 

[radios1]

I would have thought that pumps and stuff that run on a Soft Start would be three phase, since many VFDs are great at making 3 phase out of single phase if derated.

you put an oscilloscope on that, and you'll see why it's not really clean, true 3 phase!.. the motors must whistle or hum..

 

[grsthegreat]

Ive installed single phase VFD controls on alot of 3 phase machines and they run just fine. From lathes to irrigation pumps. There especially popular with center pivot irrigation motors. Now ive never placed an oscilloscope on one, but considering these controls cost in the neighborhood of $4,000 i would assume they are designed to operate a motor correctly.