theoldwizard1
Well-known member
A soft starter should be used whenever there is a limited amount of power (generator) available to charge the starting capacitor quickly !
AC Soft Start Kit
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fitter30
Well-known member
Ac compressors are psc motors.
I haven’t seen the older starter kits referred to as “soft start”, they where usually called “hard start” kits. The “hard” part was because the motor had a hard time starting due to low voltage, age, etc. They typically use a large start capacitor and a potential relay to “release “ the charged capacitor. This was how a lot of older equipment was built from the factory. I guess at some point they figured they could get by without it and removed it. Also not all of these type of motors have a centrifugal switch built in.
These newer “soft starts” seem to use the existing start capacitor and some type of electronics to alter how it’s used. The wiring I saw has you disconnecting the existing capacitor from the ac wiring and it gets connected to the soft start device.
Not sure what else happens in the soft start box, but it seems there would be more than just the start capacitor being regulated.
These newer “soft starts” seem to use the existing start capacitor and some type of electronics to alter how it’s used. The wiring I saw has you disconnecting the existing capacitor from the ac wiring and it gets connected to the soft start device.
Not sure what else happens in the soft start box, but it seems there would be more than just the start capacitor being regulated.
theoldwizard1
Well-known member
Tinkerer2
Well-known member
By "cheap soft starters" is that the category you put the Rectorseal Kickstart? If it makes the starting current WORSE, and the Easy Start is a gadget that "limits" how fast the start capacitor is charged, isn't the Easy Start start capacitor just as worse?
Rectorseal website says:
Relay drops out start capacitor at optimum time to avoid excessive heat
Avoids potential damage to compressor by never staying in the circuit too long
“Relay drops out start capacitor at optimum time to avoid excessive heat
Avoids potential damage to compressor by never staying in the circuit too long”
That’s the potential relay that has been around forever and is the key part of a hard start or kick start kit. It’s also a component that used to be in older ac equipment from the factory. My well starter box has one in it, I am guessing for the chance the impeller is stuck with sand or something and needs a kick to get it going. I don’t believe there is anything bad about these kits. But if I was trying to solve a start problem with a generator, I would probably go with one of these electronic soft starters. You have people here that are using them and say the work.
Avoids potential damage to compressor by never staying in the circuit too long”
That’s the potential relay that has been around forever and is the key part of a hard start or kick start kit. It’s also a component that used to be in older ac equipment from the factory. My well starter box has one in it, I am guessing for the chance the impeller is stuck with sand or something and needs a kick to get it going. I don’t believe there is anything bad about these kits. But if I was trying to solve a start problem with a generator, I would probably go with one of these electronic soft starters. You have people here that are using them and say the work.
like2wheel
Well-known member
I can't give you an intelligent answer other than to tell you that I needed to put a hard start kit on my 3 ton a/c unit when I self installed it 25 years ago, and it is still running with that today.
Tinkerer2
Well-known member
WOW. I thought AC units died way before 25 years.
American Locomotive
Well-known member
Lots of people way all over the place. Let's break down the three systems being talked about very simply:
- "Hard Start" kit: These are a big start capacitor with a special relay you attach to your AC compressor. These actually increase starting current. But they make the compressor start faster. They are useful if you have low voltage/voltage sag problems or your system short cycles. Sometimes they can help get your system started on a marginal generator by getting the compressor at a high enough speed before your generator bogs down too much.
- "Soft Starter": These are basically giant automatic dimmer switches. When you turn the AC on, they start out on "dim" and quickly ramp up to full power in a controlled way. It softly starts the motor, reducing peak current. Will often reduce light dimming/flicker during start, and may help get a system running on a generator. These are NOT anything like an inverter - they're basically dimmer switches in how they work.
- "Inverter": Also known as a VFD (variable frequency drive). These actually directly control the speed of the compressor. You will not find commercial "kits" to convert your system to inverter. AC systems have to be designed with them integrated from the beginning to work properly.
- "Hard Start" kit: These are a big start capacitor with a special relay you attach to your AC compressor. These actually increase starting current. But they make the compressor start faster. They are useful if you have low voltage/voltage sag problems or your system short cycles. Sometimes they can help get your system started on a marginal generator by getting the compressor at a high enough speed before your generator bogs down too much.
- "Soft Starter": These are basically giant automatic dimmer switches. When you turn the AC on, they start out on "dim" and quickly ramp up to full power in a controlled way. It softly starts the motor, reducing peak current. Will often reduce light dimming/flicker during start, and may help get a system running on a generator. These are NOT anything like an inverter - they're basically dimmer switches in how they work.
- "Inverter": Also known as a VFD (variable frequency drive). These actually directly control the speed of the compressor. You will not find commercial "kits" to convert your system to inverter. AC systems have to be designed with them integrated from the beginning to work properly.
Jim greengo
Well-known member
Throw a hard start kit on it.
pcmeiners
Well-known member
"WOW. I thought AC units died way before 25 years."
This thread may not.
This thread may not.
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theoldwizard1
Well-known member
Some inverters used on refrigeration compressors actually "create" a 3 phase output. The voltages are not the same as you would find in a commercial building, but it is 3 unique phases going to 3 unique windings in the motor.
3 phase motors are much more efficient compared to single phase so it makes up for the power lost by the inverter.
danski0224
Well-known member
The Easy Start is not just a capacitor.
There's a whole bunch of electronics in the box.
theoldwizard1
Well-known member
The electronics are not that complicated ! Check the link I put in my previous post.
Tinkerer2
Well-known member
Got the Micro-Air EasyStart installed today. Very easy install. I don't have inrush amp readings because I don't have a meter that can do that.
However, the electrical data specs for my AC unit is 75 LRA and 16.8 RLA. According to the Micro-Air app, my starting amps are down to 23.2 and running amps are 8.3. The unit starts a lot quieter too. In fact, you have to be fairly close to hear the compressor kick on with the fan running.
I'm going to test the generator tomorrow or Tuesday.
However, the electrical data specs for my AC unit is 75 LRA and 16.8 RLA. According to the Micro-Air app, my starting amps are down to 23.2 and running amps are 8.3. The unit starts a lot quieter too. In fact, you have to be fairly close to hear the compressor kick on with the fan running.
I'm going to test the generator tomorrow or Tuesday.
The AC on my RV didn't have a start capacitor, only a run capacitor. The Easy Start instruction did mention that if I had a start capacitor, to remove it. So my understanding is that it is replacing, not regulating the capacitor.
Whatever it does, it works great on my AC.
Tinkerer2
Well-known member
Tested it with the generator this morning. Worked perfectly. Generator sound didn't change at all during the AC startup. Glad I made the switch from the hard start.
kinggsxr
Well-known member
This might be off topic but would something like this help prevent my GFCI breaker from tripping when using a miter saw?
dcg9381
Well-known member
Could be. Test it. Shut down all the other breakers in the home. Turn off the AC. Turn off the main and trigger the generator. Turn on the AC. See what happens.
I have a 20KW geneset, it'll run a 2 ton, 3 ton, and 1.5 ton AC all at the same time (not start them all at the same time). One of our ACs is on a "delay" to make sure that they don't start up at once.
I've also got a monitor in the main panel so I can see what my home pulls in terms of total power. It's never gone above about 15KW.
I dunno which is better, but we use "soft start" capacitors in the RV arena all the time. I've got a 15K BTU unit with a soft start that I run on a 2500 watt generator.
vavet
Well-known member
I installed the Micro-aire unit on my residential heat pump yesterday. I forgot to borrow my clamp meter from work to get the initial inrush current, but the micro-aire app showed it was initially about 52 amps. It worked its way down to about 30 amps, and then I saw another 46 amp startup. It started cooling off outside after that so I'm not sure what the subsequent starts were.
This was all done on utility power, but the intent is to help it start more easily on generator power when we have power outages. As it is, the lights dim, the wi-fi usually has to reset, and sometimes the TV turns off...yes, I know. First world problems.
Installation didn't take long, but it does take some interpretation of the instructions because every system is a little different. Mine has a control board with some monitoring functions and two LEDs that illuminate or blink to indicate a certain pattern/meaning, but it's not the emerson control board that gets it's own set of instructions.
This was all done on utility power, but the intent is to help it start more easily on generator power when we have power outages. As it is, the lights dim, the wi-fi usually has to reset, and sometimes the TV turns off...yes, I know. First world problems.
Installation didn't take long, but it does take some interpretation of the instructions because every system is a little different. Mine has a control board with some monitoring functions and two LEDs that illuminate or blink to indicate a certain pattern/meaning, but it's not the emerson control board that gets it's own set of instructions.
Tinkerer2
Well-known member
What ton unit do you have? Which micro aire did you install? Mine is starting at about 23 and I have a 3 ton unit.
Kezorm
Well-known member
Just installed the micro-air easy start on my 5 ton ground source heat pump. What a difference! Starting current went from >150A peak down to just over 40A. Prior to easy start, the inrush was so high that you could actually hear the wires jump inside the EMT conduit and lights would flicker just a bit.
theoldwizard1
Well-known member
Any noticeable delay in starting ?
Kezorm
Well-known member
No delay. The compressor starts up smoothly and quickly. Far smoother than the jarring start from before. Generally, A/C compressors and heat pumps don’t start under any load. This is what allows method like easy start to work. It wouldn’t work with something like an air compressor that needs to start under load.
* as default, easy start has a ~5 second startup delay by design to let the fan start first, but this is by design. It doesn’t apply power at all to the compressor motor for those 5 seconds. Once power is applied to the compressor, there’s no delay / slow start at all. Just smoothly starts running vs. jarring instant dump of full voltage / high inrush current. This 5 second delay can be disabled if necessary (some compressors have diagnostic electronics that expect the compressor to start immediately)
* as default, easy start has a ~5 second startup delay by design to let the fan start first, but this is by design. It doesn’t apply power at all to the compressor motor for those 5 seconds. Once power is applied to the compressor, there’s no delay / slow start at all. Just smoothly starts running vs. jarring instant dump of full voltage / high inrush current. This 5 second delay can be disabled if necessary (some compressors have diagnostic electronics that expect the compressor to start immediately)
virtually all air compressors start "unloaded" btw. most can't start under load, necessitating an unloader. it goes "PSSSSSSSH" when it stops on the small ones.
Tinkerer2
Well-known member
Would you please elaborate on the monitor in the main panel? Brand, etc? What type of data does it give you?
dcg9381
Well-known member
See below. I bought this largely to be able to monitor overall power. I JUST use it as a monitor on the mains (it can measure solar back-feed). But it's also capable of monitoring downstream circuits inductively if you add additional pickups. Peak power use, daily power use, hourly use, various warnings if we're setting new power records, etc.
The unloaded compressor head and discharge line gets filled in a revolution or two, long before the motor gets up to speed so to some degree an air compressor starts under a load.
in air compressor parlance, "loaded start" would imply tank pressure at the 2nd stage discharge valves. dirty unloaders can cause loaded starts. the compressor at my shop was doing them for years before I got there and fixed it. it's a QR-25 5120, 25hp, 3ø, DOL starter. 4 belts.
most VFD piston pumps I've seen cannot perform a "loaded start" if the cut in is set high. the ones I've seen try will make it once there's any inertia in the system. (i.e. if the compressor stopped with the piston just past TDC, it'll start, and if it stopped BDC, it won't make the first compression stroke.) but if the motor is programmed for rated torque, it won't overcome the no inertia stall condition.
once you've made the first revolution, it's not an issue anymore.
I installed an easy start on my 23 year old 3T A/C system about a year ago. Inrush went from 115A to 23A. Here's a technical interview with the engineer who designed the easy start. Our lights used to dim when the AC came on, and it sounded like a 12ga shotgun. Now I can't even hear the thing come on when I'm standing by it until the fan gets up to speed.
When I installed my 24kW Generac about 10 years ago, I installed one of their smart modules on my A/C. The generator communicates with the module and disconnects the A/C power when the generator first starts up, and can disconnect it if the load from the rest of the house becomes too great. I installed the easy start because we had a few lengthy power outages that summer and it made me cringe when the A/C started on generator power.
When I installed my 24kW Generac about 10 years ago, I installed one of their smart modules on my A/C. The generator communicates with the module and disconnects the A/C power when the generator first starts up, and can disconnect it if the load from the rest of the house becomes too great. I installed the easy start because we had a few lengthy power outages that summer and it made me cringe when the A/C started on generator power.
Tinkerer2
Well-known member
That's a great video. Thanks for the link.