Test Report

Report Reference No.: 50337286 001
UL 1012
Clause
Requirement – Test
Result – Remark
Verdict
Page 35 of 75
26.2.3
A flanged bobbin-wound transformer shall be constructed so as
to maintain physical separation between the primary and
secondary windings. Physical separation shall be accomplished
by employing a 3-flange bobbin for winding the primary and
secondary windings adjacent to each other or using a
telescoping bobbin construction with each section containing an
individual winding where the primary winding is wound over the
secondary winding or the secondary winding is wound over the
primary winding. The bobbin insulation shall comply with note
(a), (b), (c), or (d) of Table 26.1.
Not flanged bobbin-wound
transformer
N/A
Exception No. 1: A 2-flange bobbin having the primary winding
wound over the secondary winding, or the secondary winding
wound over the primary winding with the primary winding
insulated from the secondary winding by means of tape
insulation, may be used when:
N/A
a) The tape insulation complies with note (a) or (c) of
Table 26.1;
N/A
b) The tape insulation provides a continuous1/32 inch (0.8
mm) overlap on the bobbin flanges; and
N/A
c) The transformer complies with the tests described in the
Flanged Bobbin Transformer Abnormal Test,
Section 55 (see 26.2.4).
N/A
Exception No. 2: A 2-flange bobbin having the primary winding
wound over the secondary winding, or the secondary winding
wound over the primary with the primary winding insulated from
the secondary winding by means of tape insulation, may be
used when:
N/A
a) The tape insulation complies with note (a) or (c) of
Table 26.1;
N/A
b) The coils are layer wound; and
N/A
c) All windings have end turns retained by a positive means
and the spacing between end margins of the primary and
secondary windings comply with Table 26.1(d).
N/A
Exception No. 3: A transformer complying with the
requirements in the Standard for Class 2 Power Units, UL
1310; the Standards for Low Voltage Transformers - Part 1:
General Requirements, UL 5085-1, and Low Voltage
Transformers - Part 3: Class 2 and Class 3 Transformers, UL
5085-3; or the Standard for Transformers and Motor
Transformers for Use in Audio-, Radio-, and Television Type
Appliances, UL 1411, meets the intent of this requirement.
N/A
Exception No. 4: Physical separation of the primary and
secondary windings is not required for units employing multiple
layered wire which has been evaluated to the requirements for
miscellaneous insulating devices and materials of the Standard
for Polymeric Materials - Short Term Property Evaluations, UL
746A, the Standard for Polymeric Materials - Long Term
Property Evaluations, UL 746B, and the Standard for Polymeric
Materials - Use in Electrical Equipment Evaluations, UL 746C.
N/A
26.2.4
With reference to Exception No. 1(c) to 26.2.3, the Flanged
Bobbin Transformer Test of Section 55 is not required when the
transformer:
N/A
a) Is supplied from a LVLE circuit in accordance with 6.15, or
a limited energy circuit in accordance with 6.13; or
N/A
b) Complies with the requirements in36.5 - 36.13.
N/A