Motor thermal Protection

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QES

Senior Member
Location
California
If you are using a combination starter w/ thermal overload then you are not required to use the thermal switch.
 

don_resqcapt19

Moderator
Staff member
Location
Illinois
Occupation
retired electrician
Some motors for classified areas require that you use the internal motor winding temperature switch to prevent the exterior surface of the motor from getting too hot. This requirement is more common in a Class II installation than in a Class I installation, but may be required in a Class I, Division 1 location per the last part of 501.125(A).
 

rbalex

Moderator
Staff member
Location
Mission Viejo, CA
Occupation
Professional Electrical Engineer
In this case, determining the correct answer is not a trivial exercise. In order to give a complete and accurate answer, we need to know the following:
  • The Zone 2 Group and "T-Code"?
  • The motor "T-Code" and/or insulation class (both if you can get them)
  • Does the motor nameplate or other label specify Class, Division and/or Zone; if so, what is it?
  • Does the motor have an "Ex" mark; if so, what is it? Specify Ex, EEx, and/or AEx (Any and all)
  • Any NRTL or third party certification marks (UL, CSA, FM, CE, etc.) Give full description. Example: NRTLCSACAN.
  • Manufacturer - this last is not usually critical, but may be helpful.
 

furlong

Member
The Zone 2 Group and "T-Code"?
The motor "T-Code" and/or insulation class (both if you can get them)
The T-Code is T3C

Does the motor nameplate or other label specify Class, Division and/or Zone; if so, what is it?
Class1 Div1&2. Class 21 Zone 1&2

Does the motor have an "Ex" mark; if so, what is it? Specify Ex, EEx, and/or AEx (Any and all)
Not that I could find.

Any NRTL or third party certification marks (UL, CSA, FM, CE, etc.) Give full description. Example: NRTLCSACAN.
UL listed

Manufacturer - this last is not usually critical, but may be helpful.
Baldor
 

rbalex

Moderator
Staff member
Location
Mission Viejo, CA
Occupation
Professional Electrical Engineer
Still need the Zone 2 Group & "T-Code." That is, the Group and "T-Code" for the location the motor is to be installed in.
 
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