Energy Guide

Page 49 of 104 Report No.: HK2107050725-SR
UL 507
Clause Requirement + Test Result - Remark Verdict
TRF No. UL507A
31.5.2 With reference to the secondary voltage and volt-
ampere capacity limits, the measurements are to
be made as follows:
a)The input to the source of that secondary is to be
connected as intended;
b)The maximum open circuit voltage potential
available to the secondary circuit under
consideration is to be measured across the source
of that secondary; and
c)The maximum volt-ampere capacity available to
the secondary circuit under consideration is to be
measured by connecting a variable resistive load
across the source of that secondary and then
measuring the voltage and current while varying
the resistive load from open circuit to short circuit in
1-1/2 to 2-1/2 minutes. The maximum available
volt-ampere capacity is then calculated by
multiplying the simultaneously measured values of
secondary voltage and secondary current.
N/A
31.5.3 For a transformer, only one secondary circuit of a
multiple secondary transformer is to be tested at a
time and all other secondaries not under test are to
be loaded as intended. The voltage and volt-
ampere capacity measurements are to be made
directly across the secondary output terminals of
the transformer. When a tapped transformer
winding is used to supply a full-wave rectifier, the
measurements are to be made from either end of
the winding to the tap. When the transformer is
used as part of a switching-type power supply, the
voltage and volt-ampere capacity measurements
are to be made after the transformer secondary
winaing rectification means
N/A