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Hey Maxster, Just a note to thank you for the excellent advice. Finally got back to that job, I carefully inspected the ribbon cables and indeed they were worn through!
But guess what else I discovered when placing some cardboard between the cable and
chassis? When I flexed the cable I could actually see that the top two solder connections on the cable were cold joints and would make and break!! Pulled both boards, resoldered them and ran it for three hours, no problems now. Had to shut it back down 'cause I want to make certain it throttles back properly when it hits setpoints. Thanks again. Later, Mike

thats cool on the ribbons Macon bends them as they stack the panels and have some leak a sinal causing other trips...make sure all philips head screws are tight the board on a return grounding to the power feeds to them,check all the pins rebot what you can the only fix here is if it doesn't trip any more...so time will tell.maybe flip a 1U1 module from another to see if you take the CE tripping with it...you caught that CT post about just the one on the VFD inverted wire out to the motor check the resistance on it compared to the others (check the white tag on it for number range match up.....good luck maybe get back midweek to see what results you had

Hey Maxster, I haven't megged the motor, but did do a passive resistance check prior and it was well over 20 meg on all three (actually six) windings. This is one of seven and the only one I've converted. It initially ran fine for two hours and still will sometimes. The VFD is one I've installed at least twenty of (six on different Trane units BTW) and to date have had no problems. BTW if the VFD sees anything wrong with the motor it will shut down immediately. This motor was swapped out in 2006 and is listed for vfd use. Not once has the vfd tripped. My problem is definitely in the unit somewhere. I caught your note on the ribbon cables and will inspect them closely tomorrow AM. BTW Thank you for your replies, I appreciate it. Mike.

Mike..how many unit do you have with the VFD add on after the IGVs went nuclear...nuke cleee r.now thinking about it 97 isn't bad on the motor.future applications a motor change might be in order using a motor that has seen a constant 60Hz then all of a sudden the Hz are being slid in and that voltage when it is ramping up/down can do a job on the insulation...anybody meg the motors on those jobs especially to ground maybe a heat up might cause a CE trip...Ray

Ok Thanks. The current problem I'm having has the techs in Georgia stumped, so you can imagine my dilemma. Mike.

dang.

It actually worked!!

Originally Posted by unclemikey509

Yes, I am a tech. Sorry if I violated site rules, please excuse my ignorance.
I found his reply via a bot search filled out the appropriate forms to gain access here, but must have overlooked a rule. Will leave presently.

No need for you to leave. I'd actually encourage you to stay, learn the rules (I'm still learning stuff about this site) and become a Professional Member where we can share more detailed information about the equipment we work on.

Since you are both techs, this thread will be moved to the appropriate section "tech-to-tech chat Commercial"

move it to the SWUD section...

Tech

Yes, I am a tech. Sorry if I violated site rules, please excuse my ignorance.
I found his reply via a bot search filled out the appropriate forms to gain access here, but must have overlooked a rule. Will leave presently.

Maybe I'm misunderstanding.

Unclemikey,

Are you a tech? If so, then this thread needs to be moved to the proper forum.

I am 59 so I am the older I guess. Hey,... I don't feel that old. Except recently HA!

hey,... i'm 58 who you calling OLD might go over to messeger in the site to continue we'll see if the prime movers dabble only trying to help out and their busting shoes

Maxter, I truely appreciate your advice. To the system admin: I would take this discussion elsewhere if I were more facile with computers. Just an old guy here trying to
make a unit run.

Originally Posted by maxster

i'm not a owner just answering the guys question....what's with all the rules i didn't even want PM status....... just looking to help others...

You don't need to be an owner to be an AOP Pro.

It'll take 5 minutes to fill out the form and we won't have to hassle you anymore.

i'm not a owner just answering the guys question....what's with all the rules i didn't even want PM status....... just looking to help others...

Maxster,

You're giving very good advice.

Please take a minute and apply for your AOP * before posting in AOP forum.

that was easy........... the SWUD W/inverter print shows the olfd fan contactor retagged as the driv contactor with no CTs on the L side as with CV unit.they take 1T8 and run the T3 coming out of the VFD thru it the CT is connected into the 1U1 at A4J5 pin.again the dip switch resetting will have the module look at the single CT there and not the typical # off the old CV contactor....i made up an actual static vs DC ramp signal having read them to see how the numbers move at and below setpoint.just from experience if a space is comfortable and your last cooling signal A21 just dropped off.the VFD should not be above 30Hz the VAVs should be backed down and the static SP met and even lower is cool... typical as said 55F at 1.5" static even less on the static depending on the ducted supply turns and rises.any counter rotation prior to start will trip the unit into CE,coming out of MWUP or NSB i found the control goes back up onto the VAVs for occupied,but the VFD is at 60Hz,and can't ramp down quick enough thru the 1U4 module so you can get a CE trip there.you have to dump the VAVs during unoccupied runs and the unit is looking at the return air settings for MWUP/NSB as you see on the 1U1 just throwing out stuff i remember....biggy here if you come up on a unit with the compressor CTs tripped... it's not the compressors the condensers are fouled or check the strainers the CTs will trip them before HI Pressure is tripped...that ones free

the SWUD connection to its VFD are the 1U4 ramping module,run signal NO,shutdown NC,and the 3 phase thru the old CV fan contactor.i'm rethinking the CV ..CT location on the L side of that fan contactor...i'm remember seeing one in the VFD panel as was when Magatek was the first into them with just one? have to dig print up to see if it was added or taken from the top of that SF contactor? do you have full blown SWUD prints showing a VFD wiring?on the current vs static Macon had no idea what static was in relation to effecting the motor.the staic probe as right on the fan housing in the 80s then was moved out onto the duct, before the first VAV...middle of the VAVs... end of the duct run. i'll get back on stuff

Hmmm I thought a bit more about your reply Maxter. If the unit were looking for a given amount of motor current draw for what a designer anticipated for a given static pressure and did not see that, would it actually lock out? My God, if that were true I would give a real hats off to the designer. But if I were him I would also worry about putting a unit into the field that could lock out at the slightest provocation. My prior experience w/Trane says they wouldn't do somethimg like that... Hmm

Huh? Yes we have a circa '97 board in this one(blue led's) actually they look like vacuum fluorescent to me. I miss your point about the unit driving the ct's into overload... My understanding of the circuitry is the the ct's are monitoring current draw of the IDB motor, hence I wouldn't expect them to actually do anything. The unit is operated by a 0-10vdc source (third party.. Alerton, I think) And tries to maintain a 1.5" WC static. It operated just fine on the vanes (Until they worked loose)