# You asked: What is a Class F motor?

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The F refers to the insulation class for the windings, while the B refers to an 80°C rise (the maximum temperature rise for Class B is 80°C). This type of notation is becoming more widespread because many motors use Class F insulation, and there is a reason for that.

## What is the meaning of class F?

Class F insulation consists of materials or combinations of materials such as mica, glass fibre, asbestos, etc., with suitable bonding, impregnating or coating substances, as well as other materials or combinations of materials, not necessarily inorganic, which by experience or tests can be shown to be capable of …

## What is a Class E motor?

Class E insulation consists of materials or combinations of materials, which can be shown to be capable of operation at Class E temperature, if they have a degree of thermal stability that allows them to be operated at a temperature 15 Centigrade degrees higher than Class A materials.

## What is temperature value of Class F insulation?

Temperature classes

IEC 60085 Thermal class Old IEC 60085 Thermal class Maximum hot spot temperature allowed
120 E 120 °C
130 B 130 °C
155 F 155 °C
180 H 180 °C

## How is motor insulation class determined?

The motor’s ambient temperature, internal temperature rise, the altitude (>3300 Feet) and the service factor will be the determining factors in choosing the class of insulation. The ambient temperature factor is determined by measurement of ambient air surrounding the motor.

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## What is the difference between Class H and Class F insulation?

motor with Class B insulation and a 40°C ambient temperature. This practice means that a motor with Class F insulation and an 80°C rise is referred to as an ‘F/B’ motor. Modern insulation materials means Class F insulation is commonly used for motor windings.

Too hot to handle?

A= 60°C
F= 105°C
H= 125°C

## Is class F insulation inverter duty?

Temperature rise is the difference between the ambient and the hot winding temperature. A motor with a 1.15 SF and class F insulation (for 1500 Hp and less) is rated at 125C per NEMA MG-1. … Motor manufacturers classify their motors as inverter duty when they use a class F insulation.

## Which among the following is an example of class F?

Which among the following is an example of Class F? Explanation: Paper lamination is the example of Class E.

## What is 80K temperature rise?

To allow for any Hot Spots in winding lower temperature limits are specified for the insulation materials. MEZ motors have been produced with insulation class F with winding temperature rise in accordance with the class B (max 80K). This means that the motors have a temperature reserve of 25K.

## What is class B temperature rise?

For example, an 80°C rise is often referred to as a ‘Class B’ temperature rise, since 80°C is the maximum allowable temperature rise (by resistance) for a 1.0 S.F. … motor wound with Class F insulation, a Class B temperature rise at full load translates to a thermal margin of 155- (40+90) = 25°C.