PV-250 Track Relay
Copyright 2019 SM 4574F, Rev. 4, March 2019
3-4
** The resistance value of R is selected to ensure that when the Variac is set to its
Maximum setting the value of current, as measured on meter A, is approx. 10% higher
than the maximum Full Stroke current. For the purposes of this test circuit the resistor
is fixed, however, it can be a potentiometer and set to a value that permits a 10%
higher than the maximum Full Stroke current value.
Figure 3-1. AC Vane Relay Test Circuit
Table 3-1. Shop Test Operating Values @ 70-74
°
F
Vane Torque
(Inch Grains)
Pick-Up (PU)
Full Stroke (FS)
Drop Away
% of Actual PU
Volts
(for ref. only)
Amps*
Volts
(for ref. only)
Amps*
Shop
325
2.9 – 3.3
0.048 – 0.053
3.3 – 3.6
0.053 – 0.059
85 to 95
Note:
Table 3-1 values represent nominal calibration values
±
5%. See Table 3-3 for
In-Service and Field Calibration Operating Values.
∗
The digital ammeter should be set to display to only three decimal places. Values beyond
three decimal place accuracy are insignificant to the calibration and should be ignored.
When the track energy is reduced to 1.7 volts or .028 amp, the vane must have touched
the lower roller stop. The values in
are 13% higher than ideal and apply to test from single-phase supply with
resistance in series with the track winding.
It’s recommended that relays be taken out of service if the Drop-Away falls below the value
shown for field test.
NOTE
Shop Test operating values may be affected by fluctuations
of local voltage, temperature, and test equipment being
used.
Table 3-2. Operating Values at Ideal Phase Relations
(Values shown are for technical use and for calibration tag information
only
.
Not to be used for normal calibration purposes.)
Pick-Up (PU)
Full-Stroke (FS)
Drop-Away
% of Actual PU
Volts
Amps*
Volts
Amps*
2.60 – 2.88
0.042 – 0.046
2.9 – 3.20
0.047 – 0.052
85 to 95
Note: Table 3-1 values represent nominal calibration values
±
5%.
Summary of Contents for N342555809
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