UL 474-2015 pdf download

UL 474-2015 pdf download.Dehumidifiers.
SB1 .1 Throughout the Supplement, when reference is made to requirements in his Standard,” the reference is to requirements in the main body of the Standard and not to other requirements of the Supplement.
SW .2 These requirements provide an alternative path for investigation of electronic controls used in appliances covered by this standard.
SB1 .3 In the context at this Supplement, an electronic control is a circuit incorporating at least one electronic component and that causes the intended output of the appliance energy source(s) (e.g. heaters, moving parts, humidity, radiation) to vary.
SBI .4 In the context of this Supplement a motor speed drive would be considered an electronic control.
SB1 .5 Circuits that transmit or receive signals (analog or digital). transform or convert electricity to supply other circuits (e.g. power supply) or simply switch an electrical load (e.g. electronic relay) are not controls but are subject to the requirements of this Supplement when they are integrated (physically or functionally) with a control.
SB1 .6 A self-regulating PTC heater is not considered a control from the perspective of this Supplement. When a thermistor is used as a sensor or as part of a thermal management function of a control, ills investigated as part of the control.
SB1 .7 Thermal motor protectors in direct contact with molor windings and inlended for direct control of the motor supply are outside the scope of this Supplement even if they incorporate one o more electronic components
Exception No. 1: Electronic circuits that provide thermal motor protection but only have a thermal sensor in direct contact with motor windings are within the scope.
Exception No. 2: Electromechanical thermal motor protectors in direct contact with the motor windings where the protector is connected to electronic circuits that provide the motor load control are within the scope.
SB1 .8 Electronic circuits that piovide control functions intended to prevent special hazards such as an explosion or whose failure could directly cause a hazard in the appliance are outside the scope of this Supplement.
SB3.4 ELECTRONIC DISCONNECTION — The de-energizing of the tunctional load of the appliance by an electronic device of a circuit with no air gap.
SB3.5 HAZARD OF ITSELF — The risk of fire or electric shock emanating from the electronic control
SB3.6 INTENTIONAY WEAK PART A part intended to rupture under conditions 01 abnormal operation to prevent the occurrence of a condition which could impair compliance with this standard.
SB3.7 LOW-POWER CIRCUIT — A circuit or parts of circuits farther from the supply source than a low- power point.
SB3.8 LOW-POWER POINT — A point closest to the supply source in an electronic circuit where the maximum available power to an external load at the end of 5 seconds does not exceed 15 watts.
SB3.9 PROTECTIVE ELECTRONIC CIRCUIT (PEC) — An electronic circuit that prevents a hazardous situation under abnormal operating conditions. The function of a Protective Electronic Circuit would be considered a Safety Critical Function, See clause SB3.10,
SB3IO SAFETY CRITICAL FUNCTION — Control, protection and monitonng functions which are being relied upon to reduce the nsk of fire, electric shock or injury to persons.
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SB4 Components
SB4.1 Temperature sensing, thermistor devices
SB4. 1.1 A temperature sensing device, such as a positive temperature coefficient (PTC) thermistor and a negative temperature coefficient (NTC) thermistor, that performs a Class B control function shall comply with Annex J of the Standard for Automatic Electrical Controls for Household and Similar Use, Part 1: General Requirements. UL 60730-1 – or The Standard for Thermistor-Type Devices, UL 1434. The minimum number of cycles shall be as specified In this standard. See clause 32, Heater Temperature-Limiting Control Tests; and clause 15, Switches and Controllers.