Genteq ECM 3.0 Module Teardown & Analysis

Look inside a Genteq ECM 3.0 Module. A little Hypothesizing on the construction and operation of the components. Basically this module is powered by the AC line and receives serial commands from the HVAC control board to set the motor speed. The motor is 3 phase with a permanent magnet rotor. This module originally failed to rotate the motor, it would only shake when attempting to spin up. Eventually, possibly from me powering it up with the motor disconnected it just shorted out : (

[@thomaspeters5889]

I would never fail to recognize that voice and especially that chuckle when you laugh. This is your childhood friend Tom Peters whom you first met at Freeport elementary school while you were living in Clarksburg...greetings my friend.

[@tomkirkgaard247]

Amazing to hear from you! I live in Reno Nv now.

[@miker252]

I was an HVAC Mechanic and first worked with these a few years before I retired. We serviced a site with about 20 heat pump package units. I thought of them as little VFDs built into a 3 phase motor. Most of the failures I found were with the thermistor, which I could replace to put the expensive motor back into service. I would hope that the design has improved since those days.

[@jimbofinjam1306]

Very Good; the best ECM video I've seen.

[@tomkirkgaard247]

Thak you

[@gussygoro2469]

That’s really super

[@michaelferguson8960]

Well done.

[@adtub]

HI Tom , Great info

[@Jeff-Lawrence]

Great explanation

[@ppzz7231]

thank you very much

[@rcinfla9017]

Nice tear down and analysis. The IGBT module being totally plastic cased doesn't help for heat dissipation to case heat sink. Heating may be contributor to its failure. Similar IGBT module in my Samsung VFD driven variable speed compressor refrigerator. These motors have poor power factor because of simple rectifier-filter caps used in U.S. market. European regulations require PF correction. My Samsung VFD compressor refrig has 0.60 to 0.65 power factor.

[@tomkirkgaard247]

That is a good point about the PF correction. I read other people commenting on utility waveforms are getting distorted near the sine peaks due to all the crude DC rectifiers on line.

[@dadlaponizil3687]

Thank you very much for this very thorough investigation. One of the few that actually looks at the circuitry. My big question is the communications port. Is it RS232 or? And the main question: how to control one of these without the air handler manufacturer’s control board? If it’s simple serial communications, what is the command set and protocol? Would be very nice to be able to turn it on and off and set speeds.

[@tomkirkgaard247]

I found this information on the data interface. Not exactly RS232... Interfacing the ECM 3.0 motor Communication Protocol Framing 4800 baud ± 2%, one stop bit, no parity Signaling Multiple slave/addressable Error Detection Fletcher Checksum (Complete specification document: a-8794721el_r04.pdf) Electrical Characteristics Suggested Interface circuit Data input (Rx) Input voltage range 6.5 to 20 Vdc OFF threshold, max. 2.0 Vdc DC offset max.(note 1) 2.0 Vdc Data Output (Tx) Output voltage max. 20 Vdc Output current max. 30 mA Bias supply (+V) Bias voltage range 5 to20 Vdc Current required 13 mA 1. Rx input circuit responds to both polarities. Common(C) Common

[@atubebuff]

It looks like the high-voltage DC used by the motor river and the FETs is always connected so a voltage spike that makes its way past the rectifier could damage them as their Absolute Maximum ratings are ~500-600V. MOVs would help clamp this.

[@Matt-pt8gs]

Hey Tom! I enjoyed the teardown, my ECM just quit working. It is a 1/2HP 230V unit. I don't have the RX/TX line on my connector, curious if a microcontroller is present. Are you an EE? If so, curious where you spent your career.

[@tomkirkgaard247]

Is your ECM from a condenser fan? it may only run at one speed and not need a control. I have spent decades in industrial and consumer electronics.

[@will2059]

Hey Tom, I picked at one of these for hours & it was very slow going. What was your technique for removing all that silicone potting compound?

[@tomkirkgaard247]

I think I just picked around the perimeter until I could see the edge of the pc board and pried it out from there. Have to find that ground screw and remove that first.

[@rcinfla9017]

Some potting materials will soften up a bit and become easier to pick off if you heat it up. Have to be careful with amount of heat not to damage components you want to examine. I use a butane soldering pencil with hot gas tip instead of soldering tip. Allows concentrated heat in a small area to pick off potting material in the small area.

[@andrewsnyder3359]

Very nice explanation, I was searching for characteristics of failures to Ecm motors and came across your video. The one I’m working on runs the motor but the motor is jerking at a slow speed for a few seconds then turns off, and repeats the jerking over and over. I was wondering if that would be a failed capacitor on the filter side of the power coming in, or something else? Motor windings are ok, and I tested with a good module and ops are normal.

[@tomkirkgaard247]

I assume the board is still potteded in the housing? To confirm your suspicions you could recreate the filter rectifier section outside the motor and run the DC into the power pins. Or maybe measure all three phases (phase to phase) at the motor to see if one is missing. I noticed they don't seem to like running without blower wheel. Be very careful none of of these connections are isolated from ground and have lethal voltages.

[@islandfd3s]

@@tomkirkgaard247 My motor does the same thing. It spins up just fine if I help it out. Won't spin up otherwise. Ran it like that all winter and now I'm trying to fix it. If I can't find a problem I might just change the big caps on the board and see what happens. Digging the potting out as I watch your video. I measured the (240v, 3/4hp) motor and they all read 7 ohms and none are shorted to ground so I think the motor itself is still OK.

[@islandfd3s]

@@tomkirkgaard247 Also, per your comment in the video: Mine is 3/4HP 240V and still only has the two caps. Those caps are rated at 200V 1000uF on my board.

[@dmitriyskvortsov9650]

Hi, have you figured out what was the reason for this? I have exactly the same behavior, though in my case I have 50/50 success rate, sometimes it start after few attempts. Also I bought and installed used control module, but unfortunately , nothing changed which makes me think that problem might be not the motor itself.

[@dattusonawane5372]

We have faced moto block issue X5 ..let me understand root cause

[@wpetrick6280]

If I replace the IRAMS10UP60A, Repair the board trace what value fuse should I replace the trace with? What value is the shunt resistor ? Do you think that is all the damage done to the board?

[@tomkirkgaard247]

I would guess a delay fuse slightly higher than the motor rating. I can't remember the shunt resistor .01 ohm? I never put it back in service after replacing the output module.

[@wecarespares]

Hi Tom, have you ever take apart a HD03 module? It looks very similar to the one in your video. But after I removed the ground screw and separate the silicone on the wall. I felt the board is still firmly attached to the housing, do you know if there are any other fasteners?

[@tomkirkgaard247]

There are two screws holding the power module to the heat sink. I made a little 90° pry bar to lift the board out

[@wecarespares]

@@tomkirkgaard247 You mean the processor? Yes i did undo those screws but the board is stuck to the housing. I was trying to lift the board by lifting the connector side, but somehow it won’t move at all. I thought the connector might have a clip that clips into the housing. Cheers

[@tomkirkgaard247]

@@wecarespares If you follow the green wire from the connector it has a ring terminal that has a screw that goes through the board to the housing.

[@carlwatkins8182]

@@tomkirkgaard247 Tom. I too have removed all of the silicone around the edges and all the screws. Tried using an Allen key to lift/pull at the semi-circular gap by the harness connector in the board. But there is too much silicone under the board and I'm afraid of cracking it if I pull too hard. Any other suggestions? Is there some sort of 90degree knife that I could use?

[@tomkirkgaard247]

I bent the tip on a flat blade pocket screw driver to help lift it. Wonder if heating the housing would help?

[@jesusjoelgarcia8115]

Sir you know electronics enough to be away from dirty attic, nails waiting for you head and lot of heat and dirt I hope you make lots off money thanks

[@usahoangsatruongsa]

Not too fast LOL! how about 900-1100 sq ft houses' crawlspaces ?

[@jeremiahaustin2353]

I'm trying to find a thermistor for one of these and I'm having difficulty. I'm working with Mouser to see if they have one, but I guess what's on the side of it doesn't quite tell them enough. Do you know where to find the right one?

[@tomkirkgaard247]

I would try a SL22 1R020 Digi-Key Part Number 570-1041-ND Any ntc 1 ohm 20 amp

[@Gopher599]

@@tomkirkgaard247do you know if the 1hp ecm would use the same thermistor or does it need the 1 ohm 30 amp? Thank you.

[@tomkirkgaard247]

@@Gopher599 Not that critical. If you're running it off 120V you could use the higher rating. If it 240V the 20A should work.

[@michaeltemple895]

Did you replace that garbage with a PRC motor?

[@tomkirkgaard247]

No. I use the 500 rpm circulation mode during the air conditioning season.

[@rubencastillojr4645]

The most n. U said I'm not sure. I'm switching u off