Soft Start vs Hard Start for Compressors/Motors?

[ultrarunner]

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?

 

[om21braz]

You'll get some more technical advice than I have, but it all depends on the load which device is "best" or needed. An unloaded motor, say a motor turning a grinding rock versus one starting a compressor in a best case scenario require different methods of starting to most efficiently start and aid longevity. Determine exactly what the application is and that (energy efficiency, reliability, quick startup, etc.) will heavily factor in to if an additional device is helpful or maybe a necessity. I'll leave startup amp loads, high inertia loads, etc. particulars to those better equipped to explain the fine details.

 

[caver]

Look into Leaders in Custom Marine & RV A/C Controls, Soft Starters & Displays – Micro-Air, Inc.. I was going to get one for my last RV but then I sold it and just bought a bigger genny to replace my HondaEU2000i

 

[ultrarunner]

Yep... I'd like to do more with my Honda EU 2200i to power a small portable compressor.

Thinking larger it would be nice to be able to power Central A/C with the EM 5000.

Have yet to put my meter on the A/C to measure start up load.

Thinking larger... At work electricity is billed using demand factor... Been able to mitigate years ago by staggering start times and later with Johnson controls optimum Start/Stop.

At one time everything in the clinic started at 5 am... 6 package units, ventilation, etc... quite a spike.

 

[Industrial Toys]

I am just playing with my Powerbox, trying to get it ready for sale. Brand new, Generator, Welder, American Eagle Compressor. Trying to figure it out. Noticed an unloader valve, not connected to the pressure switch. Never knew such a thing existed.

Anyway, For soft start, one would have to somehow keep pressure off the pump until it came up to speed.

 

[grsthegreat]

Believe me, after many, many generator installs for owners having AC AND HEAT PUMPS. Look into Hyper Engineering soft start. After installing one of these in my own 4 ton ac unit, i went from near 97 amp starting load to around 22 amp(as i recall...about 22 amp). My generator hardly notices the ac starting up.

Look at post #4258. Heres an actual example of cheap hard start kit vs true soft start capabilities. https://www.tractorbynet.com/forums...-your-last-generator-maintenance-run-107.html

 

[ultrarunner]

Your endorsement is good enough for me...

Is there a difference between Hard Start and Soft Start or is it marketing?

 

[Industrial Toys]

Of course there is a difference. A motor can take many times it's running current to get started. Not with soft start.

Downside is complexity and cost. And another pice of expensive equipment that you cannot possibly repair when it fails. Then you are stuck with nothing in an emergency.

 

[ultrarunner]

Of course there is a difference. A motor can take many times it's running current to get started. Not with soft start.

Downside is complexity and cost. And another pice of expensive equipment that you cannot possibly repair when it fails. Then you are stuck with nothing in an emergency.

Here is a link to Goodman Hard Start Kit

GOODMAN Hard-Start Kit, Compressor Saver, Hard-Start Kit - 38GM4'|'CSR-U-1 - Grainger

Seems this Hard Start Kit and Soft Start both designed to assist with starting load.

 

[Popgadget]

Here’s a recap of my post on the other thread. I just installed a Hyper Engineering “Sure Start” soft start device on a Goodman 3-1/2 ton heat pump. I had previously installed a 521 Hard Start kit. Here are the peak measurements from each as captured on my Fluke clamp on. I have to say that I was surprised and impressed with the outcome. I would say that the soft start is worth the $275 price tag.
To be clear, the first measurement was with the hard start kit installed.

 

[Popgadget]

Believe me, after many, many generator installs for owners having AC AND HEAT PUMPS. Look into Hyper Engineering soft start. After installing one of these in my own 4 ton ac unit, i went from near 97 amp starting load to around 22 amp(as i recall...about 22 amp). My generator hardly notices the ac starting up.

Look at post #4258. Heres an actual example of cheap hard start kit vs true soft start capabilities. https://www.tractorbynet.com/forums...-your-last-generator-maintenance-run-107.html

Actually the comparison was with a 5-2-1 start kit, which is a “good” hard start device costing over twice what the cheap Supco cost.

 

[pmsmechanic]

So is "hard start" and "soft start" just marketing nomenclature for the same thing?

 

[Popgadget]

Nope. My experiment showed that a soft start reduced the starting current of the hard start by a factor of 5.
This was comparing a 5-2-1 hard start to a hyper engineering “sure start’ soft start device which cost about 10 times the hard start.

 

[jaxs]

I can't think of any way the same load consumed roughly 1/2 the amps unless volts were doubled. Can we agree that work is done by watts? "IF" soft start double's volts momentarly,wouldn't genny see the same watt output? Maybe volts are stored for use like amps are stored by capacitors in hard start kits. :lightningbolt::detective:
You really jumped a rabbit this time Runner. :confused3:

 

[pmsmechanic]

Nope. My experiment showed that a soft start reduced the starting current of the hard start by a factor of 5.
This was comparing a 5-2-1 hard start to a hyper engineering “sure start’ soft start device which cost about 10 times the hard start.

One of us has missed something.

I read the title line as two different brand name attachments for starting motors. "Soft Start" and "Hard Start" Otherwise why would Hard Start be capitalized in the title line? I quite likely could be wrong on that.

I understand what a "Soft Start" does as farmers in the area use them on their irrigation motors to save on demand charges. So what exactly is "Hard Start"? Is it the brand name of a type of soft start or is it how a motor starts when it is hooked up to power without a device attached that reduces the number of amps used to get the motor up to speed?

Maybe now someone can answer my question. "So is "hard start" and "soft start" just marketing nomenclature for the same thing?"

 

[ultrarunner]

Yep... Wondering if Hard Start and Soft Start add on devices simply marketing terms for similar products.

 

[jaxs]

I can say for certain that hard start kits work. I've installed a countless number on hvac compressors that either was tripping breaker,trying to start then going out on overload,intermittenly starting or a little of all three. IMO hard start and delayed start should be on every unit from the factory so I've put many on as a preventive while installing new unit or servicing. In simple terms,power is stored in a capacitor and released when compressor starts. I don't know what soft start does and how it does it so I've curious.

 

[grsthegreat]

Yep... Wondering if Hard Start and Soft Start add on devices simply marketing terms for similar products.

. No, not the same thing. ALl i know is i have had ac units that have hard starts installed, but still not operate on a generator work when hard start is removed and soft start installed. Heres a short read

Faq sure start surestart hyper engineering soft start soft start

 

[RoyKing]

We should say smart versus dumb hard start. Many motors have 2 caps on them, one for start and another for run. Better designed units don't start the blower and compressor at the same time. Also many units already have a start cap installed. The start capacitor is removed from the circuit after startup usually by a relay using back emf. So cheap units just take a rough guess based on unit running draw amps or tonnage. The smart unit is able to control the size and duration of the capacitor connection by monitoring back emf and maybe line load. Thus tailoring the boost size and duration.
Without the wiring diagram or physical inspection hard to say what you have in HVAC. So without this info you are just guessing, many say HVAC's don't have start caps, use dual caps, start and run in one can, but they are under sized. What I've found is that capacitors with time degrade due to moisture. So maybe you should just replace your start cap as the first step. If you really don't have one then then inspect the unit you are buying making sure the cap is sealed can type, but hard to judge the emf relay quality. Many people report failure of add on kits in less than 24 months.

 

[Popgadget]

In simple terms,power is stored in a capacitor and released when compressor starts. I don't know what soft start does and how it does it so I've curious.

Actually, that’s a common misconception. The Start Capacitor causes a phase shift in the power supplied to the start winding, giving the magnetic field better geometry to get the rotor turning. The reason that 3 phase motors don’t use a start capacitor is that with 3 phases 120 degrees apart, there is already good geometry for getting the rotor started.

A soft start does essentially the same thing as a hard start, except that the capacitor is switched by thyristors rather than a relay. The “magic” is in the circuitry that controls the thyristors. It lets the current ramp up slowly so the rotor is already in motion by the time it gets full power, reducing the initial spike.

It was doing the research to figure out if the soft start devices were snake oil that piqued my interest enough to try one and measure the result.