UL 1090-2016 pdf download

UL 1090-2016 pdf download.Electric Snow Movers.
26 General
26.1 The periom of a snow mover is to be investigated by subjecting the required number of samples to the applicable tests described in 27.1 — 40.3. Insofar as is practicable, the tests are to be conducted in the order in which they are presented.
262 For a snow mover having a single voltage rating, such as 115 V. maximum rated voltage is considered to be 120 V. For a snow mover nominally rated 230 V. maximum rated voltage is considered to be 240 V. If the rating is given In terms of a range of voltages, the maximum rated voltage is considered to be the highest value of the range — 120 or 240 V minimum respectively.
27 Leakage Current Test
27.1 The leakage current of a snow mover rated for a nominal 1 20-V supply when tested in accordance with 27.2 — 27.6 shall not be more than 0.5 mA.
27.2 All exposed conductive surfaces are to be tested for leakage currents. The leakage currents from these surfaces are to be measured to the grounded supply conductor individually as well as collectively where simultaneously accessible. Parts are considered to be exposed surfaces unless guarded by an enclosure that has been investigated and found to be acceptable to reduce the risk of electric shock — see 7.1 — 7.10. Surfaces are considered to be simultaneously accessible if they can be readily contacted by one or both hands of a person at the same time, These measurements do not apply to terminals operating at voltages that are conskfered to be nonhazardous.
27.3 If a conductive surface other than metal Is used for the enclosure or part of the enclosure, the leakage current is to be measured using a metal foil with an area of 10 by 20 cm in contact with the surface. It the surface is less than 10 by 20 cm, the metal foil is to be the same size as the surface. The metal foil is not to remain in place long enough to affect the temperature of the snow mover.
27.4 The measurement circuit for leakage current is to be as illustrated in Figure 27.1. The measurement instrument is defined In (a) — (d). The meter that Is actually used for a measurement need only indicate the same numerical value for a particular measurement as would the defined instrument. The meter used need not have all the attributes of the defined instrument.
a) The meter is to have an input impedance of 1500 resistive shunted by a capacitance of 0.15 mF.
b) The meter is to indicate 1.11 times the average of the full-wave rectified composite wave form of voltage across the resistor or current through the resistor.
C) Over a frequency range of 0 — 100 KHz, the measurement circuitry is to have a frequency response — ratio of indicated to actual value of current — that is equal to the ratio of the
impedance of a 1500 fl resistor shunted by a 0.15 mF capacitor to 1500 fl. At an indication of 0.5 mA, the measurement is to have an error of not more than 5 percent at 60 Hz.
d) Unless the meter is being used to measure leakage from one part of a snow mover to
another, the meter is to be connected between the accessible parts and the grounded supply conductor.
27.5 A sample of the snow mover is to be tested for leakage current starting with the as•received condillon but with Its grounding conduclo4, II any, open at the attachment plug. The as-received condition is without prior energization, except as may occur as part of the pioduction line testing. The supply voltage is to be adjusted to 120 V. The test sequence with reference to the measuring circuit — Figure 27,1 — is to be as follows:
a) With switch Si open, the snow mover is to be connected to the measuring circuit. Leakage current is to be measured using both po&tions of switch S2, and with the snow mover switching devices in all their normal operating positions.