vacbox.jpg
I just completed a vac box based on many of the designs created here with cooling intake, cooling exhaust, vacuum intake, and vacuum exhaust all separated into different compartments. I have (4) 230V LH motors, with 2 being my primary on one switch and another two being the backup, separated by a check valve, on another switch.
The larger hole in the center of my box is for a supplemental fan to blow cool air cross the motors and exhaust the other end and out of my shop. I have my table set up in 4 zones, with a 1/2" muffler/filter serving as the vacuum intake cooling. With only one zone open and my primary motors on, I get about 6.5". It goes up to 8" with all 4 on.
The problem is that the motor temps go beyond 160 degrees withing 2 minutes of running. I have a thermostat mounted on the aluminum housing on one of the motors, but it only goes up to 158 degrees, so I just shut it down. I've seen where many guys report operating in the 120-130 range, and I don't understand what I am doing so differently. The temp in my shop the last few days has been 85-90, so I'm sure that doesn't help.
I have them wired to a single 30A breaker through double pole switches. Other than that, nothing special. I do notice that a small spark shoots out all of the motors about one every 3 or 4 starts. That's a bit concerning and doesn't seem normal. Could I have something wired wrong?
There isn't much of a difference in my version than many of the others posted here. In fact, I added the extra cooling as a backup and to mainly keep the extra hot air out of my hot shop. Any tips and suggestions are much appreciated.