VSD IGBT Change York Air Cooled Chiller HVAC Training for HVAC Technician

today we're going to be changing the 
igbt this is a raptor drive on a york   they refer to this as the vsd each one of these 
screws is a capacitor so every one of those so   this particular one's got one two three you've got 
eight capacitors total on this power assembly this   whole setup here is known as the power assembly 
for the drive you've got your snubbers your igbt   which is also known as an inverter each one of 
these is an output leg to the motor we're feeding   dc volts into the igbt and then we're outputting 
a ac current to the compressor motors to do this   change we've already verified it but you're going 
to read across those terminals and you want to   verify through dc volts that you have zero uh that 
you after you do a power down it takes the bleed   resistors 10 to 20 minutes to fully power that 
capacitor bank down you need to give it that time   before you start putting your hands in it verify 
that that bank is fully discharged otherwise you   will become the discharge we're going to replace 
our snubbers so when you go to do this job always   make sure you want to change these snubbers out 
these are just little filter capacitors that   go on there that help kind of clean the input 
voltage coming off of the dc bus what you want   to be careful with is that you don't over torque 
anything and and crack any of the ceramic in the   process and this plug here is pretty simple 
just a straight comes right off no big deal   and set everything aside if you'll set your meter 
to capacitance uh so it'd be this one up here and then these are designed for a one micro farad   at 10 percent variance you're going to read across 
there just like you'd read a regular capacitor and we got one on the dot that's what we want 
to look for so these are still good but they're   really cheap and fairly disposable parts so we 
definitely these are worth changing out and you   can see just you got physical cracking on the 
housing this thing has been running hard and   hot for many years so it is definitely time to get 
let this one retire you're next gonna pull these   and you're gonna pull these uh brass or copper 
these copper plates out get those out of your way he's sitting there and he's pulling there's eight 
of these little uh allens that go through and and   hit both sides of the igbt board so we got to 
pull these little allens out and once he does that   then we'll be able to fully pull the 
entire igbt assembly out yes from here   you should be able to grab it now it may may 
or may not be easy now keep in mind the back   so there are some yeah the plates you have to 
slide it out from under that nice and gentle there you go just like that the next step 
is going to be we'll take the igbt board   the new one and we're going to take 
the factory paste they send with it   and just make sure we get a good even coat now we 
need to make sure that all that paste that's there   is soft and malleable it can't be hard if any 
of it is hard or has hardened or gotten crusty   anything of that nature it can get in the way 
of the new one creating a proper seat and if   that's where the paste is supposed to help give a 
thermal barrier to where it transfers heat better   but any obstruction will not allow it to transfer 
properly and you'll struggle with it overheating   and getting an inverter over temp alarm just right 
down the middle you're going to just put a bead on   all three and whatever extra you have left over 
just kind of squiggle it around because what   will happen is we want we want it to build up and 
then compress out so that way it evenly spreads one corner on opposite ends that'll help it align 
and then you want to evenly tighten this plate   down so that everything smushes out properly 
so your first goal is just for the alignment   these are the new snubbers that they are 
sending with them these little black things   they've they've changed a couple of times over the 
years so they used to you could buy the old white   ones now you've got these little black ones so now 
that we've got the plate down and tightened down   we're just putting the snubbers back in and we'll 
be able to tighten that piece of the circuit down   and then we'll come back up to the front here 
and we will get the power cables hooked back up   last critical part is this plug is what goes to 
your logic board and operates that igbt assembly   what you really need to do is after you plug it 
back in you're going to take a little thermostat   screwdriver and you're just going to gently push 
it in and just depress that terminal down one of   the things that can happen is it will between 
plugging unplugging it and plugging it back in   the pins in these won't fully seat into the 
bottom pins and it'll cause a little bit of a   communication issue and this drive this board 
won't function properly and you'll have just   random little issues or igbt faults whatever so if 
you go through and do that that is a really handy   uh just trick that will eliminate a lot of those 
problems now a lot of people will tell you that   anytime you change a igbt you want to change 
this cable with it and while there is a lot of   truth in that in my personal experience 
i've not had significant issues with it   and unless i'm already having an issue with 
the plug i typically won't do that up front but   there are a lot of people especially that work for 
the factory that will actually recommend that so   you can make that personal choice as to whether 
or not you feel that's necessary according to   your situation from there our next step would be 
to power it up make sure we don't have any faults   everything's communicating like it needs to and 
then turn the circuit on now the caveat here is   i won't get to show you that today because we're 
still pulling a vacuum and what's going to finish   and whatnot before we'll actually be able 
to get this turned back on and start it up   so genuinely i don't expect any issues done 
this a number of times really smooth really easy   process but mtt guys take care of 
your family take care of your spouse   that's how you do an igbt on a york raptor 
vsd also known as just a vfd same thing

pexels photo 11039667

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