FED-STD-228A
Method 1621.1
18 APRIL 2014
ANGLE, WRAP
1. SCOPE
1.1 This method is intended for use in determining the angle which the yarns of cotton wrap make with
the axis of the insulated wire or cable.
2. SPECIMEN
2.1 The specimen should be a piece of the inspection unit at least 6 inches in length from which any
covering over the wrap has been removed.
3. APPARATUS AND REAGENTS
3.1 The apparatus and reagents shall be as described in the methods referenced in 4.
4. PROCEDURE
4.1 The specimen shall be free from mechanical damage. The length of lay shall be determined as
described in method 1531 and the value recorded as L.
4.2 The diameter over the wrap shall be determined as described in method 1141 and the value
recorded as D.
4.3 The wrap shall then be removed from the specimen and the diameter over the core (assembly under
the wrap) shall be determined as described in method 1141, and the value recorded as D1.
4.4 If two wraps are present, the angle of the outer wrap shall be determined from the diameter over the
inner wrap.
5. RESULTS
5.1 Calculation. The tangent of the angle of the wrap at any place shall be calculated as follows:
Tangent of angle = š(D+D1)
2L
where:
D=the diameter over the wrap or serving, inch
D1=the diameter over the core, inch
L=the length of lay of one spiral of wrap
š=3.14
5.2 The angle of the wrap shall be determined from the tangent of the angle by reference to a table of
natural trigonometric functions.
55
For Parts Inquires call Parts Hangar, Inc (727) 493-0744
© Copyright 2015 Integrated Publishing, Inc.
A Service Disabled Veteran Owned Small Business