TM 9-6115-604-34
NAVFAC P-8-633-34
WARNING
Generator set must be shut down and MAINTENANCE LOCK-OUT switch S1O set to
MAINTENANCE during following procedure. Failure to observe this precaution may result In
death by electrocution.
(1)
Remove
(a)
Shut down the generator set in accordance with the Operator and Organizational Maintenance Manual. Be
sure MAINTENANCE LOCKOUT switch S100 has been set to MAINTENANCE.
(b)
Open upper cabinet B door.
(c)
Tag and disconnect wires from transformer T105 terminals.
(d)
See Figure 10-8. Remove hexagon head capscrews (11) and lockwashers (12) to remove KVAR meter
transformer T105 (13).
(2)
Install
(a)
See Figure 10-8. Install KVAR meter transformer T105(13) and secure with lockwashers (12) and screws
(11).
(b)
Make wiring connections to T 05 terminals as tagged. Remove and discard tags.
(c)
Close upper cabinet B door.
SECTION III. TRANSDUCERS
10-5. GENERAL. The purpose of any transducer is to accept an input signal, alter the signal, and present the altered
form of the signal at the output of the transducer. This output is then used by some external device that could not have
used the original, unaltered signal. The generator set contains four transducers: current transducer AMT, frequency
transducer Al 03, power factor transducer PFT, and watt transducer WMT. These transducers perform as follows:
a.
Current Transducer AMT. Current transducer AMT is located inside the upper part of cabinet B and receives
input signals from current transformers CT10, CT11, and CT12. The output of the transducer is applied to AC
AMPERES meter M102 through AMMETER switch S114 and LOCAL REMOTE switch S2. Current transformers
CT10, CT11, and CT1 2 sense the load current through generator G1 output lines T3, T2, and T1, respectively.
At rated load, each output line carries 130 amperes, producing a current of 3.71 amperes in each current
transformer. Current transducer AMT monitors this current, and as it varies from 0 (no load) to 3.71 amperes,
the transducer generates a corresponding input signal from 0 (no load) to 0.74 (full load) milliampere dc. This
signal is applied to AC AMPERES meter Ml 02 and results in an AC AMPERES reading from 0 to 130 amperes.
AMMETER switch S114 is used to select phase A (T1), B (T2), or C (T3) for reading. Current transducer AMT
processes the current transformer signal of each phase separately. The AMT output for each phase is
continuously present; AMMETER switch S114 determines which set of output terminals are connected to AC
AMPERES meter Ml 02 at a given time.
b.
Frequency Transducer Al 03. Frequency transducer Al 03 is located inside the upper part of cabinet B and
receives an input signal from the secondary of potential transformer T104. Transformer T104 is a high accuracy
(0.6 percent) 20:1 step-down transformer tied to generator G1 output line T1. Transducer Al 03 produces an
output signal to drive the movement of HERTZ meter Ml 03. The transducer and meter are factory calibrated in
conjunction with each other and supplied as a matched set.
c.
Power Factor Transducer PFT. Power factor transducer PFT is located inside the upper part of Cabinet B and
receives a voltage input from potential transformers T106 and Ti07 and a current input from current transformer
CT12. Transducer PFT produces a 0 to 500 microampere dc output that is directly proportional to the phase
angle difference between the voltage and current at the input. The polarity of the output current indicates
whether the phase angle difference is a lead or a lag. The output of transducer PFT is applied through LOCAL
REMOTE switch S2 to POWER FACTOR meter Ml 04. Meter Ml 04 indicates from 0.5 power factor lagging to
0.5 power factor leading.
d.
Watt Transducer WMT. Watt transducer WMT is located inside the upper part of cabinet B and receives voltage
and current inputs from potential transformers T104 and T106 and current transformers CT1 0, CT1 1, and CT1
2. The transducer provides a 0 to 1000 microampere output that is directly proportional to the power flowing
through generator GI output lines.
10-17
