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slippage of the knob pointer on the shaft, this can
be corrected by rotating the shaft fully CCW. N ow
adjust the knob at the pin prick mark. This should
return the knob to its original position on the shaft
and bring the scale markings back into calibration .
If components in the breaker failure timer cir
cuit have been replaced it may be necessary to
change the scale plate and recalibrate. First
jumper test points TP6 and TP7. Using a low
bounce initiate switch adjust timer knob until a 2 5
ms time delay h a s been obtained. Use test
procedure described under acceptance testing for
measuring time delay . N ote the knob position for
25 ms delay. Also note the knob position for 1 75
ms delay . Loosen the set screw and position the
knob on the shaft so that the 2 5 and 1 75 ms
locations are equidistant about the knob locking
tab. Scribe lines at the 25 ms setting and for each
25 ms increment up to 1 75 ms.
Indicating Contactor Switch ( I C S)
Adjust the contact gap for approximately
.04 7" by adjusting the stationary contacts. Both
contacts should make simultaneously.
Check to see that the contacts close at rated
tap value current. The indicating target should
drop at or just prior to the contacts closing . The
targer should drop freely .
If the target does not drop or does not reset it
may be necessary to remove the cover an9 bend the
tab on the spring that supports the target.
TRO UBLE SHOOTI N G
T h e components in the S B F- 1 relay are
operated well within their rating and normally will
give long and trouble free service. However, if a
relay gives indication of trouble in service or dur
ing routine checks the following information will
prove helpful. All measurements are approximate
and may vary as much as 20% . All voltages are
positive with reference to common negative (relay
terminal 8) except ac voltages.
Timer Module
I.
Jum per test points TP6 and TP7.
8
a . Apply rated relay voltage. Voltage at lower
test jack = 23 . 5 V
b . Rem ove jumper . Apply rated v oltage .
Voltage at lower test jack = less than 2 . 5
Vdc.
2. Jumper test points TP6 and TP7
a. Apply rated relay voltage. Voltage at upper
test jack = less than 2 . 5 Vdc.
b. Rem ove jumper. Apply rated v o ltage.
Voltage at upper test jack = less than 2 . 5
Vdc.
3. Jumper test points TP6 and TP7 .
a . Apply rated voltage. Voltage at terminal 6
of I C 1 = 1 8 . 3 V .
b . Rem ove j umper . Apply rated voltage.
Voltage at terminal 6 of I C 1 should be ap
proximately 0 . 1 Vdc less than voltage
measured in section a.
4. Jumper test points TP6 and TP7.
a . Apply rated relay voltage. Voltage at ter
minal 7 of I C l = 20.8V with timer knob fully
CW.
b. Voltage at terminal 7 of I Cl = 23 . 8 V with
timer knob fully CCW.
5 . Jumper test points TP6 and TP7.
a . Apply rated relay voltage. Voltage at ter
minal 2 of I C 1 = 1 6 . 5 V .
b . Remove jumper a n d apply voltage. Voltage
at terminal 2 of IC 1 should be approxi
mately 0. 1 V less than voltage m easured in
section a.
6. Apply twice tap value ac current.
a. A pply rated relay vo ltage . V o ltage at
TP3 = 1 2 .7 V . Voltage at TP4 = less than
0.5V.
b . Interrupt ac current. Voltage at TP3 = less
than 0 . 5 V . Voltage at TP4= 1 2 .7V.
7. Apply rated voltage to relay terminal 18 (52a
input).
a. Apply rated relay voltage to terminal 9 .
Voltage at TP4= less than 0 . 5 V .
b. Reduce voltage t o terminal 1 8 to 60% of
rated relay voltage. Voltage to TP4 = 1 2 . 7 V .
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