ICM RapidStart HSK

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FionaZuppa

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Part Time Electrician (semi retired, old) - EE retired.
Ever see a wiring diagram like this before. Does it not show the run coil with shorted ends? It's a ICM805.
I assume it's not a tie between the CCC's. And even if that's the case, start and run load is passing through the ICM toroid?
 

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rjk_cmh

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Columbus, Ohio
The updated PDF diagram on ICM's website is slightly more clear, and shows an additional fuse between the start cap and the triac switch. The bridge you see labelled 'line' should be broken with the word line in between it, representing the incoming phase conductors.
 

FionaZuppa

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AZ
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Part Time Electrician (semi retired, old) - EE retired.
TY RJK, but the label I posted is literally a sticker on the HSK. Yeah, I know it's wrong, was just checking with the rest of the MH crew.
But notice how every diagram has the non-Common Line leg wire passing through the ICM coil loop. ICM did tell me they only need to monitor the HERM amps (the Start winding) and that looping that wire would be best. But is there not a diff in amps between the ICM diagram you posted vs just looping the HERM through the HSK? Isn't the diagram in your post Start+Run, where as if it's just the HERM wire it's only the Start winding amps? If say the ICM HSK is tuned for a 35A cutout then the ICM diagram would have the ICM cap cutout before there was 35A on the start coil. Am I missing something here?
 

rjk_cmh

Member
Location
Columbus, Ohio
Yes it makes sense that you might only want to monitor the start winding, but I suspect that the device isn't tuned for a specific amperage, and rather looks for a spike and then a dip within a certain time frame to determine when to open the triac.

In the PDF you posted, all of the various diagrams for different applications show the line running through the CT, and not just the start, and I suspect that this is related to some of the following features that are listed in the table following those diagrams:
  • Self Adjusting
  • Uses Current Differential Technology
  • Senses Whether Motor Started or Not
etc. But I can't speak for the manufacturer as to exactly how the device works, so it's mostly conjecture.
 

FionaZuppa

Senior Member
Location
AZ
Occupation
Part Time Electrician (semi retired, old) - EE retired.
Yes it makes sense that you might only want to monitor the start winding, but I suspect that the device isn't tuned for a specific amperage, and rather looks for a spike and then a dip within a certain time frame to determine when to open the triac.

In the PDF you posted, all of the various diagrams for different applications show the line running through the CT, and not just the start, and I suspect that this is related to some of the following features that are listed in the table following those diagrams:
  • Self Adjusting
  • Uses Current Differential Technology
  • Senses Whether Motor Started or Not
etc. But I can't speak for the manufacturer as to exactly how the device works, so it's mostly conjecture.
I am not sure how it works, yet. Will take the cover off and take a peak at what's there.

As a side topic, I am curious about adding all this extra Start torque, because adding torque has impact on the mechanical side of this, and it seems this is not a topic with plentiful discussion anywhere.
 
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rjk_cmh

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Location
Columbus, Ohio
The kicker cap in the HSK reduces the inrush amperage because it is correcting the phase angle on the start winding during startup. Normally, the current applied to the start winding is not at the most optimal angle, which causes the winding to approach saturation and pull significantly more current while not doing much effective work.

Once the phase angle is correct, the start winding works with the main winding more effectively instead of just barely leading it along based on the run cap's rating. The phase angle coming out of a cap is a function of the current that is flowing through it, and during normal run you need lower capacitance to get the correct angle. But when the machine is starting, the increased amount of current means that you need more capacitance to get the correct angle, otherwise the start winding is dragging along and pulling more current to do less work.

As for the torque, think of a machine that is specced for 3-phase - in such a system, you always have the ideal phase angle and maximum starting torque, and those work fine mechanically.
 

FionaZuppa

Senior Member
Location
AZ
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Part Time Electrician (semi retired, old) - EE retired.
RJK
When adding more MFD in series with an inductor there's gonna be more amps flowing, keep adding more and more MFD and the ckt will look more like just an inductor. The phase shift that comes in the dual coil motor is indeed the key for higher torque, but w/o a cutout switch for the extra MFD the start will still be at LRA, and, there would be more amps in the Start coil during run time, which also affects running rpm. Not good. Is this correct?

As for 3ph torque, yeah, it has "best" torque, but all of the mechanical stuff was designed to handle that torque, from motor components to whatever mechanical load is attached. We all know that adding too much torque can torque shear a shaft in two.
 
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rjk_cmh

Member
Location
Columbus, Ohio
Once the rotor is up to speed, the back-EMF will increase, which reduces current. But this is where my theoretical knowledge starts to get a little dim - my understanding is that if the start cap remains connected, it will resonate with the start winding at an incorrect frequency, which may cause saturation - which pulls more current and blows up the start cap.

The cap is just there to cause the current to lead the voltage, it doesn't necessarily change the magnitude of the current. That can only be done as a function of voltage and resistance, and as we know the effective "resistance" is based on what's happening with the inductor - amount of back-emf, whether it's in saturation, etc.
 

FionaZuppa

Senior Member
Location
AZ
Occupation
Part Time Electrician (semi retired, old) - EE retired.
Here's an update:

Swapped out a pot-relay HSK (5-2-1 CSR-U3) for a ICM 805. Results are a tad of a head scratcher. Here's some tidbit info.

The Copeland motor has LRA of 127 - but I have no idea how that is tested, like what wiring harness is used, what size wiring, what the supply looks like. But ok, use that as a base #. My initial amp-clamp (inrush) of line did seem to indicate a LRA #. Run amps were around 8start/12run (~20A line).

With the initial install of the 5-2-1 the unit was starting with an obvious increase in torque. Nobody seem to know what an increase in start torque does to the mechanical side of the Copeland motor/compressor unit. Increasing torque within the same short time period equates to mechanical impact forces. This I am studying as an aside to these HSK's. With the 5-2-1 installed my amp-clamp (inrush) indicated near 46A. Seemed like an improvement from LRA.

Ok, I wanted to move over to a solid-state HSK and chose the ICM805. The condenser wiring did not accommodate the recommended ICM805 wiring diagram so I had to re-wire just a tad. Since the OEM setup split off Cap-Start and Run line at the contactor via two #12's, I converted that over to two #12's into a #10 (2-to-1) up to a terminal block. This #10 (line) loops through the ICM per ICM wiring diagram. The term block then feeds the cap with a #12 and the run coil with a #10 patch down to the motor's #12 run wire.

Upon 1st inrush test of the ICM I found it to be near LRA. Hmmm, odd, didn't seem right. Amp-clamped the motor start wire (while running) and had zero, and line amps were now near 25A. Ok, something not right, yanked wires and took mfd readings..... run cap (70mfd) is reading zero! Lucky for me I had a spare 60mfd, so installed that. And even with a dead start cap, the Copeland still started.

Here's where things get interesting. with the 60mfd and ICM805 installed, line inrush was still reading near/at published LRA. I was tad baffled, was then wondering maybe the 805 was a bad unit, so took the 805 wires off and did another start-up line inrush reading, and it metered in at 151A !!!

So now I am a tad baffled. Did using a 2-to-1 (two #12 to one #10, soldered) to term block, and, using a #10 to feed the motor run #12 (approx 6" worth of #10), be enough new wire capacity to allow 151A on start-up (w/o the ICM)?? Duly noted, OEM setup used spade terminals on everything, so maybe some contact issue there? My #10 from term block to the motor #12 is a proper soldered connection, and all the connectors I had to do are soldered (two spades to contactor and three eyelets on the term block). With the ICM805 in place, its seems to knock off ~30A from start-up, but will contact ICM and ask if that's the expected results.

I am not able to at this time do some data logging (amps vs time) between using the 5-2-1 vs the ICM805. I have the gear to do it, just not the time right now. I am wondering if the pot-relay of the 5-2-1 was simply cutting out sooner than the ICM805 does. Pic of relay is also attached so you can seen cut-in and cut-out settings. The cap will have near 380v on it during run time. I believe the caps used in both the ICM and 5-2-1 HSK's are about the same. Duly noted here, amp # alone doesn't tell the whole story, it's really area under the curve of amps vs time that tells us how much power is being used for the time period. So w/o data logging it, simply cannot see that with basic meters, etc.

Anyways, some interesting stuff if you ever get to dig into AC condenser to install an HSK.


relay2.png ICM805-2.png
 

FionaZuppa

Senior Member
Location
AZ
Occupation
Part Time Electrician (semi retired, old) - EE retired.
Just to note, post #3, yes, that's the "wiring" gram they show, but it's very not accurate to call that a wiring diagram. It's more of a schematic mixed in with a pictorial. It's doesn't even show the two wires that come out of the ICM, etc. If ICM has been doing electronic controls for a long time,,,, then I can only shake my head in wonder.
 

FionaZuppa

Senior Member
Location
AZ
Occupation
Part Time Electrician (semi retired, old) - EE retired.
Well, just a few days after install the ICM805 sheet the bed. Total junk. Will stick with the 5-2-1 for now.
 
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