UL 1411:1998 pdf download Transformers and Motor Transformers for Use in Audio-, Radio-, and Television-Type Appliances
Scope
1.1 These requirements apply to transformers, autotransformers, and motor-transformers intended to beused in audio-, radio-, and television-type appliances in which the primary winding is connected acrossthe supply circuit.
1.2 The requirements in Sections 4 – 15, 23 – 26, 28, and 29 also apply to transformers intended for usein high-frequency, switching-type power supplies in which the transformer provides isolation from thesupply circuit.
1.3 These requirements do not apply to transformers that are intended to transform only audio, video, andother signal wavetorms. Those transtormers are covered by the Standard for isolating Signal andeedback Transformers for Use in Electronic Equipment, UL 1876.
.4 These requirements apply to a transformer or motor transformer that includes a separatecurrent-limiting impedance such as a positive temperature coefficient (PTC) device complying with therequirements for thermistor-type devices, or a resistor complying with the Standard for Fusing Resistorsand Temperature-Limited Resistors for Radio and Television-Type Appliances, UL 1412.
1.5 A product that contains features, characteristics, components, materials, or systems new or differentfrom those covered by the requirements in this standard, and that involves a risk of fire or of electric shockor injury to persons shall be evaluated using appropriate additional component and end-productrequirements to maintain the level of safety as originally anticipated by the intent of this standard. Aproduct whose features, characteristics, components, materials, or systems conflict with specificrequirements or provisions of this standard does not comply with this standard. Revision of requirementsshall be proposed and adopted in conformance with the methods employed for development, revision, andimplementation of this standard.
2 General
2.1 Components
2.1.1 Except as indicated in 2.1.2, a component of a product covered by this standard shall comply withthe requirements for that component.
2.1.2 A component is not required to comply with a specific requirement that:
a) lnvolves a feature or characteristic not required in the application of the component in theproduct covered by this standard, or
b) ls superseded by a requirement in this standard.
2.1.3 A component shall be used in accordance with its rating established for the intended conditions ofuse.
2.1.4 Specific components are incomplete in construction features or restricted in performancecapabilities. Such components are intended for use only under limited conditions, such as certaintemperatures not exceeding specified limits, and shall be used only under those specific conditions.
2.2 Units of measurement
2.2.1 When a value for measurement is followed by a valued in other units in parentheses, the first statedvalued is the requirement.
2.3 Undated references
2.3.1 Any undated reference to a code or standard appearing in the requirements of this standard shallbe interpreted as referring to the latest edition of that code or standard.
3 Glossary
3.1 For the purpose of this standard the following definitions apply.
3.2 ENCAPSULATION COMPOUND – A material, generally of the polymeric type, that is at least 1/32inch (0.8 mm) thick (when solidified) and that covers the transformer windings.
3.3 HOUSING – A partial or complete enclosure, generally of polymeric material or metal, that isaround the outside of all or part of the transformer (such as end bells) but is not in contact with current-
carrying parts.
3.4 IMPREGNATION COMPOUND – A coating material less than 1/32 inch (0.8 mm) thick, generally ofthe polymeric type and commonly in the form of varnish, that is absorbed by insulating materials suchas electrical grade paper.
3.5 LAYER-WOUND TRANSFORMER – A transformer in which all of the turns in each layer of eachwinding are in a single plane. Turns in each layer are wound tightly next to each other with no gapsbetween them and the turns do not cross over other turns in that layer or the adjacent layers.