eamesyi
Electrical
- May 9, 2014
- 2
Hi fellas,
My company has had some problems with a spray booth we installed in a body shop awhile ago (7.5kW motors for intake/extraction fans(x2) supplied by VSDs, gas burner, PLCs, small 3-phase motor for an air compressor, a couple spot welders, pressure washer and normal shop tools, lights, etc.) The spray booth has been installed exactly as every other spray booth we have sold has and uses the same components, and we haven't had problems before. The problems we are having are:
1. 2x failed VSDs (both internal fan failures) [We replaced both of them (at different times, within a month of each other and haven't had any problems with them since (about 1 month has passed]
2. 1x overloaded motor (tripping the circuit breaker) [Replaced with a new motor and everything worked fine. We tested the problem motor, but nothing was out of the ordinary]
3. Operation drop outs consistent with communication interruptions (eg. countdown timer display on the HMI touchscreen stops, starts and jumps, but the timer continues to accurately countdown until it starts going negative at the end. This is during a cool down cycle and prevents the booth from exiting this cycle.
4. The PLC had a failure of one of its output pins that turned on the motor. Replaced PLC and everything is working correctly.
In general as we've replaced the problem components everything would work perfectly for a few weeks to a month before we'd begin having more problems. This has been going on for 5 months now.
The environmental conditions worth noting beyond the energy consuming tools listed above are:
1. the fact that there is a wash bay right next to (less than 5 meters from the control panel and VSDs) and there is no physical segregation. The VSDs and control panel are not IP rated for that environment and is a major concern of mine. I have not seen the site, nor the spraying that they actually do, but the experienced electrician has seen it and doesn't think it is the problem.
2. The area is in central Queensland, Australia so it does get hot and we have just finished our summer (40 deg days are not unusual)
3. There is no separate instrument/comms earth and they join the main power feed at the control panel with a 6mm earth cable running 50m to the main DB (MEN connection) which then runs out to the earth stake.
I've attached the data from the data logging instrument we used to see if there was any harmonic issues. I have no idea how to read the report and would really appreciate some input to see if we can rule out system harmonics as the cause of the problems.
My company has had some problems with a spray booth we installed in a body shop awhile ago (7.5kW motors for intake/extraction fans(x2) supplied by VSDs, gas burner, PLCs, small 3-phase motor for an air compressor, a couple spot welders, pressure washer and normal shop tools, lights, etc.) The spray booth has been installed exactly as every other spray booth we have sold has and uses the same components, and we haven't had problems before. The problems we are having are:
1. 2x failed VSDs (both internal fan failures) [We replaced both of them (at different times, within a month of each other and haven't had any problems with them since (about 1 month has passed]
2. 1x overloaded motor (tripping the circuit breaker) [Replaced with a new motor and everything worked fine. We tested the problem motor, but nothing was out of the ordinary]
3. Operation drop outs consistent with communication interruptions (eg. countdown timer display on the HMI touchscreen stops, starts and jumps, but the timer continues to accurately countdown until it starts going negative at the end. This is during a cool down cycle and prevents the booth from exiting this cycle.
4. The PLC had a failure of one of its output pins that turned on the motor. Replaced PLC and everything is working correctly.
In general as we've replaced the problem components everything would work perfectly for a few weeks to a month before we'd begin having more problems. This has been going on for 5 months now.
The environmental conditions worth noting beyond the energy consuming tools listed above are:
1. the fact that there is a wash bay right next to (less than 5 meters from the control panel and VSDs) and there is no physical segregation. The VSDs and control panel are not IP rated for that environment and is a major concern of mine. I have not seen the site, nor the spraying that they actually do, but the experienced electrician has seen it and doesn't think it is the problem.
2. The area is in central Queensland, Australia so it does get hot and we have just finished our summer (40 deg days are not unusual)
3. There is no separate instrument/comms earth and they join the main power feed at the control panel with a 6mm earth cable running 50m to the main DB (MEN connection) which then runs out to the earth stake.
I've attached the data from the data logging instrument we used to see if there was any harmonic issues. I have no idea how to read the report and would really appreciate some input to see if we can rule out system harmonics as the cause of the problems.
