Drew
08-09-2015, 08:11 AM
Hi all,
I was called to a site where there had been a fire alarm and evacuation after smoke was smelt.
I found a three phase contactor that fed a duct heater bank fused in . The fan had turned off and this one stage got hot and caused smoke. The safeties had kicked in , but due to the fact that the contactor had fused nothing turned the heater bank off.
We isolated the system and ordered new stats,APS, etc.....
ive checked the heaters to not be down to earth using a mega at double applied voltage and they show to be clear.
The strange thing is I've found the fusses to be blown.
the sequence of events could be:
A) fused contactor
b) fan stop
c) elements get hot
D) fusses blow?
Does a heater draw high amps if it gets hot? The heaters when working draw 24amps with a 35 amp fuse. I'm trying to figure out why the fusses blew if the elements are not down to earth? Or do they go down to earth if they get too hot and when cool they are clear?
I was called to a site where there had been a fire alarm and evacuation after smoke was smelt.
I found a three phase contactor that fed a duct heater bank fused in . The fan had turned off and this one stage got hot and caused smoke. The safeties had kicked in , but due to the fact that the contactor had fused nothing turned the heater bank off.
We isolated the system and ordered new stats,APS, etc.....
ive checked the heaters to not be down to earth using a mega at double applied voltage and they show to be clear.
The strange thing is I've found the fusses to be blown.
the sequence of events could be:
A) fused contactor
b) fan stop
c) elements get hot
D) fusses blow?
Does a heater draw high amps if it gets hot? The heaters when working draw 24amps with a 35 amp fuse. I'm trying to figure out why the fusses blew if the elements are not down to earth? Or do they go down to earth if they get too hot and when cool they are clear?