hazardous location motor thermostat leads
hazardous location motor thermostat leads
(OP)
A customer had a 5hp 480v 3 phase motor in a class 1 division 1 area that was being relocated.It is controlled by a
xp manual starter.While disconnecting from original location I found 2 wires for thermostat in motor junction box that were wirenutted together.The question is do I need to use them?The motor is rated for hazardous location and has overload protection in the manual starter.
xp manual starter.While disconnecting from original location I found 2 wires for thermostat in motor junction box that were wirenutted together.The question is do I need to use them?The motor is rated for hazardous location and has overload protection in the manual starter.





RE: hazardous location motor thermostat leads
Yes you must connect them in series with the overload circuit. If the motor is overheated for watever reason, the temperature rise shall be limited by the thermostats before ignition temperatures for the Class and Group are reached.
RE: hazardous location motor thermostat leads
RE: hazardous location motor thermostat leads
Repair shops, I believe, need to install these devices on motors they repair. In Alberta, there used to be a standata that required us to connect these devices if they were present; this requirement no longer exists in Alberta's standata as of about 2 years ago.
RE: hazardous location motor thermostat leads
The answer is YES,
The Explosion proof motors have one or more thermostats in order to trip(BY DESIGN) before the frame reaches the maximum allowable temperature for the specific class and group. The normally closed contacts of the thermostat must be connected in the motor control circuit so that power to the motor is removed immediately when the thermostat trips.
Regards
Petronila
RE: hazardous location motor thermostat leads
CEC 22.2, 145-1972 section 6.3.4
Read also Hazardous Locations by Bossert chapter 19 Repair Facilities. Chapter 19
Repair and contstruction of motors and generators is contolled and audited by CSA at qualified facilities all across Canada not by Alberta Standata.
RE: hazardous location motor thermostat leads
RE: hazardous location motor thermostat leads
Where exactly in CEC 22.2 145 is it required that explosion proof motors NEED a thermostat ( or similar device )? They are allowed to have them. And if they have them, they must be operable when the motor is tested on the over temperature test. But a motor does not seem to need to have a thermostat ( or similar) device to pass a CSA temperature test. Refer to 7.3.1 of the standard.
By the way, my copy of the document by Bossert ( 1986) doesn't have 19 chapters.
Repair of motors is definitely defined by CSA standards and requires a thermally sensitive device installation in the motor at repair; however, the connection of thermal devices in the field has nothing to do with motor construction - it is motor installation. It is installation that is impacted by Standata.