Which is Better Class B or Class F insulation?
Which is Better Class B or 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 |
|---|---|
| B= | 80°C |
| F= | 105°C |
| H= | 125°C |
What is class F insulation?
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 …
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.
What is class F insulation temperature?
What is meant by “Class” in insulation?
| Insulation Rating | Insulation Class | Average Winding Temperature Rise |
|---|---|---|
| Class 150 or 130 | B | 80 degree C |
| Class 180 | F | 115 degree C |
| Class 200 | N | 130 degree C |
| Class 220 | H | 150 degree C |
Can a Class F motor be used with a VFD?
Motors made during that time were not made for VFD use, but if they are VFD rated, will be okay. Class F insulation or higher is suitable for VFD use, but VFDs may have no more than a 2:1 Constant Torque ratio. Existing condition of motor insulation systems may be the determining factor in this case, and conducting a High Pot Test is recommended.
What kind of insulation do you need for a VFD?
Class F insulation or higher is suitable for VFD use, but VFDs may have no more than a 2:1 Constant Torque ratio. Existing condition of motor insulation systems may be the determining factor in this case, and conducting a High Pot Test is recommended. 2.
What’s the difference between Class F and F motor insulation?
Insulation “Class” has to do with temperature rise, not voltage spikes. VFD controlled motors should have higher VOLTAGE ratings on the winding insulation, but that is NOT reflected in the class rating. Class F is a really good idea, but not an absolute. If for instance your pumps are in a well ventilated space, Class B would probably be fine.
What is the effect of variable frequency drive on motor insulation?
Owing to the fast developments on power electronics, presently this frequency reaches easily values such as 20 kHz. The higher the switching frequency, the faster the degradation of the motor insulation takes place.