Ul approved transformer

[engineer1000]

A have a 300W transformer that I need UL approval on it consists of a plastic bobbin with ETD34 3C90 ferrites. We are using litz wire (UL approved) seperating the primary and secondary using polyester tape (UL approved) The ferrites also have UL approval.
My question is is does the transformer need to be vacuum impregnated to get over all approval.
Is this the case?

 

[tpetar]

What country and region ?

What I know this is different, and depends from region and country. I supose you mention UL for US.



UL 506 Special Transformers
UL 544 Medical and Dental Equipment
UL 131 Direct Plug-in Transformers
UL 1585 Class 2 and 3 Transformers



What are the UL standards that users of transformers should be interested in? The significant UL
standards for users of transformers include:

UL506 Specialty Transformers -- covers the requirements for particular construction methods,
dielectric strengths and a maximum operating temperature rise for power transformers rated 10.0
KVA or less.

UL544 Medical and Dental Equipment -- covers equipment in which transformers may be used.
Requirements for transformers recognized to UL544 include a limit on leakage current, some means
of internal thermal or current fusing, or a manufacturer-specified external current fuse, and either
double insulation or an electrostatic shield between primary and secondary.

UL1411 Transformers and Motors for Use in Audio, Radio and Television Type Appliances -- like UL544, this is an equipment standard to which a transformer can be recognized. Requirements for
transformers recognized to UL 1411 are very similar to UL506. The major difference is a
requirement for the use of UL94VO listed material (flame retardant) for terminal anchoring points
and the abnormal performance testing required per end product specifications.

UL1585 Class 2 and Class 3 Transformers -- covers current-limited devices designed to protect
against the consequences of an overload. They can be either inherently or non- inherently currentlimited.
Inherently current limited transformers are constructed so that during a long-term
overload, or short-circuit, they will not produce a fire. Non-inherent current-limited transformers
contain either a current or a thermal fuse to

 

[engineer1000]

What country and region ?

What I know this is different, and depends from region and country. I supose you mention UL for US.



UL 506 Special Transformers
UL 544 Medical and Dental Equipment
UL 131 Direct Plug-in Transformers
UL 1585 Class 2 and 3 Transformers



What are the UL standards that users of transformers should be interested in? The significant UL
standards for users of transformers include:

UL506 Specialty Transformers -- covers the requirements for particular construction methods,
dielectric strengths and a maximum operating temperature rise for power transformers rated 10.0
KVA or less.

UL544 Medical and Dental Equipment -- covers equipment in which transformers may be used.
Requirements for transformers recognized to UL544 include a limit on leakage current, some means
of internal thermal or current fusing, or a manufacturer-specified external current fuse, and either
double insulation or an electrostatic shield between primary and secondary.

UL1411 Transformers and Motors for Use in Audio, Radio and Television Type Appliances -- like UL544, this is an equipment standard to which a transformer can be recognized. Requirements for
transformers recognized to UL 1411 are very similar to UL506. The major difference is a
requirement for the use of UL94VO listed material (flame retardant) for terminal anchoring points
and the abnormal performance testing required per end product specifications.

UL1585 Class 2 and Class 3 Transformers -- covers current-limited devices designed to protect
against the consequences of an overload. They can be either inherently or non- inherently currentlimited.
Inherently current limited transformers are constructed so that during a long-term
overload, or short-circuit, they will not produce a fire. Non-inherent current-limited transformers
contain either a current or a thermal fuse to

Thank you for your answer, with regards UL544
Our transformer has double insulation between primary and secondary of yellow polyester tape (UL approved). The board it's on is fused on the live and neutral lines. the litz wire we are using is UL as is the plastic bobbin and EDT ferrites.The transfomer is wrapped in black acetate cloth tape ( which is not UL approved). Now some companies are saying the transformer needs to be vaccum impregnated other are saying it doesn't. Really what I am looking for is a yes it does or no it doesn't answer