HEAT LOSS DATA FOR SINGLE PHASE TRANSFORMERS IN CLASSES F, E & A

& HIGH EFFICIENCY SINGLE PHASE TRANSFORMERS FOR IP65

AND Ex ENCLOSURES

 

 

Losses for Class F (155 deg C) transformers

 

Losses for Class E (120 deg C) transformers

 

Losses for Class A (105 deg C) transformers

 

Losses for IP65 or for Ex enclosed transformers

with frame size data
 

The data shown is provided to help design engineers select the correct insulation classification for transformers. The heat loss data is important when transformers are fully enclosed or housed in confined control panel situations.

 

Standard stock transformers are Class E insulation.

Standard custom built single phase and three phase transformers are either Class E or Class F insulation.

 

Non standard Class A insulation (105 deg C) transformers are for lower watt loss per VA.

Class A designs are suitable for UL requirements utilising all approved UL registered and approved materials.

 

To allow for transformers to be enclosed in IP65 Ex rated cabinets high grade Grain Oriented core materials are used.

Selection of enclosure must be based on the heat loss data provided.

 

Definitions and Data

 

Insulation Class Coding Temperature Rating Max Temp Rise Max Ambient Temp
Class F SF 155 deg C 115 deg C 35 deg C
Class E SE 120 deg C 85 deg C 35 deg C
Class A SA 105 deg C 70 deg C 35 deg C

High efficiency types in IP65 or Ex enclosure for guidance only, for specific applications contact our sales dept.

C - Core losses are at nominal input voltage   W - Winding losses (approx) are at full load

Heat loss data for single phase transformers from 7kVA to 30kVA

and

Heat loss for 3 phase transformers from 120VA to 100kVA

on request