SERVICE MANUAL R5888C
QUADRAMHO Chapter 2
Page 72 of 74
6.20 DC supply ratings and operative range
Three versions of the power supply are available with nominal ratings as shown
below.
DC supply Vx (1) nominal operative maximum
range withstand
48/54V 37.5 – 60V 64.8V
110/125V 87.5 – 137.5V 150V
220/250V 175 – 275V 300V
Effect on accuracy of impedance measurement due to dc supply variations within
the operative range of the relay is negligible.
6.21 Auxiliary dc supply for optically-coupled isolators
DC voltage Vx(2) for the opto isolators may, if required, be different from the
power supply voltage Vx(1). Available nominal voltages and operative ranges of
Vx(2) are as listed above for Vx(1). Threshold of operation for opto isolators not
less than +10V (to provide immunity from electrical noise).
6.22 DC power consumption
Typical under healthy live line conditions 25W
Maximum under tripping conditions 50W
6.23 Inbuilt continuous monitoring and periodic self-test
There is continuous monitoring of power supplies, clock pulses, scheme logic and
ac voltage supplies and a selectable periodic self test of all 18 measuring elements
(selected via SW5) every 2 weeks.
Time taken to perform self test = 0.085s
6.24 Voltage withstand
Insulation
IEC 60255-5 2kV rms for 1 minute between all case terminals
connected together and the case earth terminal.
BS142 1982 Section 1.3 2kV rms for 1 minute between independent circuit
of the scheme, including contact circuits.
1kV rms for 1 minute across normally open
outgoing contact pairs.
High voltage impulse
IEC 60255-5 5kV peak, 1.2/50µs, 0.5J between all terminals
BS142 1982 Section 1.3 and case earth and between adjacent terminals.
High frequency disturbance
IEC 60255-6 Class III 2.5kV peak between independent circuits and
between circuits and case earth.
BS142 1982 Section 1.4 1.0kV peak across input circuits.
1Mhz bursts decaying to 50% of peak value after
3 to 6 cycles.
Repetition rate 400s
–1
.
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