PV-250 Track Relay
Copyright 2019 SM 4574F, Rev. 4, March 2019
3-7
Table 3-3. In-Service and Field Calibration Operating Values
Current
(Amps)
Acceptance Criteria*
Pick Up (PU)
0.048 Min. – 0.053 Max.
Front contacts should be “closed”
Full Stroke(FS) Max.
0.053 Min. – 0.059 Max.
Vane should touch upper roller
Min. Drop Away (DA)
% of Actual PU is 80%
Equal to or Greater Than
80%
×
PU
Front contacts should be “open”
Full Drop Away (FDA)
0.028 Amps Min.
Vane touches the lower roller stop
*
If relays don’t meet the Acceptance Criteria they must be shopped
for readjustment and recalibration.
Table 3-4. Contact Assignments
Coil Connections
Contacts*
WINDING Old Style Base
Location
New Style Base
Location
Type
Old Style Base
Location
New Style Base
Location
Local
L+
10E
Fronts
7F (Front)
11B (Front)
7H (Heel)
12B (Heel)
L-
10F
8F (Front)
11C (Front)
8H (Heel)
12C (Heel)
Control
C1+
1A
Backs
9H (Heel)
11E (Heel)
9B (Back)
12E (Back)
C2-
2F
10H (Heel)
11F (Heel)
10B (Back)
12F (Back)
* Contacts are standard low-voltage silver-to-silver impregnated
carbon fronts
and silver-to-silver backs.
3.3. Contact Resistance
Resistance of front contacts should be measured with the armature in its full-stroke
position, and resistance of back contacts should be measured with the armature fully
released. Cleaned contact resistance should not exceed the values shown in Table 3-5.
Table 3-5. Contact Resistance (Ohms)
Type of Contact
Front Contacts
Back Contacts
Silver-to-Silver Impregnated Carbon
0.09
--
Silver-to-Silver
--
0.03
Contact surfaces should not be disturbed unless there is evidence of severe pitting from
excessive loading or an accidental short through the contacts. When contacts must be
Summary of Contents for N342555809
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