Section V Model 11 153A 1
Table 53. VAC Reed Relay Checks.
1
POSSIBLE CAUSE/
CHECK RESULT INSTRUCTIONS
1. Apply 100 mV, 1 kHz to input Reading increases when input Perform Check 2. 1
on 100 mV range in VAC(AC) and is applied in both VAC(AC) and
then in VAC(DC). VAC(DC). (Readings may be noisy
or inaccurate.)
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Reading increases in VAC(AC) only. A7K2 open
Reading increases in VAC(DC) only. A7K1 open.
1
Steady or overload reading in A7K11 open.
both VAC(AC) and VAC(DC). Note: If A7K11 is not
open, perform Check 4.
2. Connect an AC Voltmeter to Approx. 1 Vac at A7TP1. Perform Check 3. 1
A7TP1 and the input LOW
terminal. Approx. 10 mVac at A7TP1. A7K3 and A7K4 shorted,
Select 1000 mV range, VAC(AC) or A7K3 and A7K5 shorted.
Apply 1OOOmV. 1 kHz. I
3. Select 1000 V range, VAC(AC) Approx. 500 mV at A7TP1. Perform Check 4.
Apply 100 V, 1 kHz.
Approx. 1 V at A7TP1. A7K4 open, or A7K5 open.
Approx. 8 to 10 Vac at A7TP1, A7K3 open, or r
~~ A7K4 and A7K5 open.
4. Remove ACVM form A7TP1. Reading is below 10% of range Perform Check 5.
Connect short across input on all ranges. I
terminals. Switch through
all ranges. Reads Overload on 100 mV and A7K7 open.
10 V ranges.
Reads Overload on 1000 mV A7K8 open. 1
and 100 V ranges.
Reads Overload on 1000 V range. A7K6 open.
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5. Apply 100 mV, 1 kHz on Readings are 100 mV f 10% Perform Check 6.
100 mV range VAC(AC), and 1000 mV * 10%.
and then apply 1000 mV
on 1000 mV range. 100 mV range out of tolerance. A7K6 shorted, or
A7K8 shorted. I
1000 mV range out of tolerance. A7K7 shorted.
6. Select 1000 mV range, VAC(DC) Settles to final reading in Perform Check 7. I
Apply 1000 mV, 10 Hz. approx. 15 seconds.
< 2 counts noise.
Settles in 3 to 4 seconds. A7K10 shorted.
Excessive noise. I
Responds in approx. 15 seconds. A7K9 open (A7K9A in
Excessive noise. instruments below
Serial No. 100). I
7. Select lo00 mV range, VAC(AC). Settles to final reading Reed Relays not at
Apply 1000 mV, 1 kHz. in 1 to 2 seconds. fault.
Settles to final reading A7K9 shorted 1
in approx. 5 seconds. (A7K9A in instruments
below Serial No. 100).
Settles to final reading A7K10 open. I
in approx. 15 seconds.
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ACEC
