250W HPS Lighting Issue

[tan_man]

I have a lighting issue in a compressor building. The light fixtures are 250W HPS single phase 240VAC (seven fixtures total). They are located in a building adjacent to two (2) three horse power cooling fans. When these cooling fans turn on randomly, the light fixtures turn off and then slowly come back on automatically. Both fans do not usually turn on simultaneously. The fans are 3 phase 240VAC. I have not had the opportunity to check inrush current and voltage. I am wondering if installing VFDs for the cooling fans would be the best solution for the lighting issue. This issue never occurred until the fans were installed about a year ago. One fan motor has already burnt up and replaced since initial installation about a year ago. Thoughts?

Thank you for any input

 

[LEO2854]

I have a lighting issue in a compressor building. The light fixtures are 250W HPS single phase 240VAC (seven fixtures total). They are located in a building adjacent to two (2) three horse power cooling fans. When these cooling fans turn on randomly, the light fixtures turn off and then slowly come back on automatically. Both fans do not usually turn on simultaneously. The fans are 3 phase 240VAC. I have not had the opportunity to check inrush current and voltage. I am wondering if installing VFDs for the cooling fans would be the best solution for the lighting issue. This issue never occurred until the fans were installed about a year ago. One fan motor has already burnt up and replaced since initial installation about a year ago. Thoughts?

Thank you for any input

Sounds like the fans are dropping the voltage enough to cause the lamps to lose the arc and they have to cool down to restart, so the inrush current pretty high. How much current do these fans draw normally?

 

[GoldDigger]

I have a lighting issue in a compressor building. The light fixtures are 250W HPS single phase 240VAC (seven fixtures total). They are located in a building adjacent to two (2) three horse power cooling fans. When these cooling fans turn on randomly, the light fixtures turn off and then slowly come back on automatically. Both fans do not usually turn on simultaneously. The fans are 3 phase 240VAC. I have not had the opportunity to check inrush current and voltage. I am wondering if installing VFDs for the cooling fans would be the best solution for the lighting issue. This issue never occurred until the fans were installed about a year ago. One fan motor has already burnt up and replaced since initial installation about a year ago. Thoughts?

Thank you for any input

You say that the fans turn on "randomly". If they turn on frequently enough you may be exceeding the number of across the line starts per hour, causing motor overheating. That would also argue for putting in VFDs to reduce the heating load of motor starting. There is also the possibility that the motor overloads have been tweaked to too high a setting because they were doing their jobs protecting the motors.
Finally, a voltage drop large enough to cause the arcs to drop out would likely cause the motors to draw excess current for a longer time as the result of slow acceleration.

 

[Electric-Light]

What's the line voltage? If you're seeing 220v or less, I bet you have a 208v service which is more common than 240v these days. If this is the csae, you need to change the ballast tap or replace it if that's not an option. 240v lights will work on 208v, you're walking on thin ice and every little thing will drop out.