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How sensitive are VFDs to dust?

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Forum topic by Tyrone D posted 04-30-2012 04:14 AM 2602 views 0 times favorited 10 replies Add to Favorites Watch
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Tyrone D

314 posts in 988 days


04-30-2012 04:14 AM

The title says it all.

I want to mount my VFD (Teco FM50-203-C) on the front of my cabinet where the magnetic switch used to be but it is almost right under the hole for the blade tilt wheel. The saw is a right-tilt and the VFD will be mounted on the right side of the saw cabinet so it wont get as much exposure to the dust.

I am not going to mount the VFD on the wall.

Thanks.

-- --Tyrone - BC, Canada "Nothing is ever perfect, we just run out of time."


10 replies so far

View TopamaxSurvivor's profile

TopamaxSurvivor

14750 posts in 2331 days


#1 posted 04-30-2012 06:29 AM

I should be rated for NEC Article 500 Class II for that application. Keep it cleaned out!

-- "some old things are lovely, warm still with life ... of the forgotten men who made them." - D.H. Lawrence

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Tyrone D

314 posts in 988 days


#2 posted 04-30-2012 07:29 AM

I highly doubt the dust would ignite in the VFD. It doesn’t make any sparks, err shouldn’t make any sparks. Any sort of dust lying around would’ve ignited when I turned my bandsaw on. The motor makes a spark; needs cleaning.
The enclosure is rated IP20. I didn’t get NEMA 2 or 4 as I’m not made of money. They were something like 350 compared to the 185 for an IP20 rated VFD.

-- --Tyrone - BC, Canada "Nothing is ever perfect, we just run out of time."

View BobM001's profile

BobM001

388 posts in 986 days


#3 posted 04-30-2012 08:03 AM

I would blow the dust if any off the heat sink fins for the SCR’s after each use. If it has a fan and an air inlet a piece of the air filter media that you cut for a window shaker in the inlet wouldn’t hurt. Just make sure you check/clean it often.

-- OK, who's the wise guy that shrunk the plywood?

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MedicKen

1599 posts in 2117 days


#4 posted 04-30-2012 03:15 PM

Why not mount the VFD to the wall and use the existing magnetic switch on the saw to control it?

-- My job is to give my kids things to discuss with their therapist....medic20447@gmail.com

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Tyrone D

314 posts in 988 days


#5 posted 04-30-2012 04:09 PM

It seems very silly to me to mount a part of the saw on the wall and have to run wire to and from the VFD up the wall that the saw isn’t even mounted on. The table saw is in the center of my shop. I’m selling the magnetic switch and replacing it with a box attached to the fence rails like most new saws. I like to be able to turn stuff off with my leg rather than putting the workpiece on the table and freeing up one hand to turn it off, it’s also better for safety reasons.

-- --Tyrone - BC, Canada "Nothing is ever perfect, we just run out of time."

View TopamaxSurvivor's profile

TopamaxSurvivor

14750 posts in 2331 days


#6 posted 04-30-2012 04:45 PM

Never put a controller or disconnect down stream on the load side of a VFD! Good way to wipe it out ;-(

-- "some old things are lovely, warm still with life ... of the forgotten men who made them." - D.H. Lawrence

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Fuzzy

292 posts in 2644 days


#7 posted 04-30-2012 04:54 PM

From what I’ve read, you’re not supposed to place ON/OFF devices downstream of the FM-50 a it can overload the unit and destroy it. It does, however have terminals on it for connection of remote switches, so you can push one button to power up the unit, then control everything remotely. I have one that I’ll be wiring unto an old DeWalt GA saw in the near future, so I guess I;ll be doing a bunch of research on it’s functions.

-- - dabbling in sarcasm is foolish … if you’re not proficient at it, you end up looking stupid … ... ...

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BobM001

388 posts in 986 days


#8 posted 04-30-2012 05:09 PM

All VFD’s start/stop via a digital input on their control board. They also can be configured for remote start/stop. Control voltage is generally supplied by the drive itself. It’s usually 24VDC. That means the control wiring can be done with multi conductor t-stat or shielded cable. There are most likely wiring diagrams that show this. They can be configured for a start/stop station just as you describe. A “drop” that feeds the saw motor could be fed with SJTO or SOW cord. This start/stop station would be all you would mount to the saw in a location of your choice. A large mushroom head stop button can be swapped out in place of the one shown on the station. This makes it easy to just give the control a “hip check” to shut the saw down. I’m assuming that you are using a VFD becasue you have a 3 phase saw motor but only a single phase power supply. I’m also assuming that this power is 230VAC. OK, an amp rated 4 conductor twist lock plug/recepticle at the saw would allow you to disconnect the saw from its power source without the hassle of unwiring the saw. Your power drop could be run overhead with a “loop” that would keep it out of the way during cutting and give you some “room to move” if necessary.

-- OK, who's the wise guy that shrunk the plywood?

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MedicKen

1599 posts in 2117 days


#9 posted 04-30-2012 08:09 PM

Here are ajust a couple of wiring diagrams for wiring a VFD and a remote push button station. The remote is a low voltage, 12V, circuit. The push buttons control the VFD NOT the motor. While it does extra wire to run this way I found it easier to use a 7 conductor cable which allowed only 1 cable from the wall to the saw.

Here is the push button on my saw.

-- My job is to give my kids things to discuss with their therapist....medic20447@gmail.com

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MedicKen

1599 posts in 2117 days


#10 posted 04-30-2012 08:15 PM

Back to the original question of dust. I have a TECO FM50 on a Powermatic drill press that is mounted directly to the press with no cover. It is exposed to the surrounding dusty environment and has been for the past few years. I have not seen nor had any issues with it what-so-ever. All I have done is wipe of the loose dust and used some compressed air to carefully clean the dirt off.

-- My job is to give my kids things to discuss with their therapist....medic20447@gmail.com

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