Maintenance Electrician A Test Firm BTA-C

Using the schematic at left, what would the wire number be that marked "X" on SOL A if you were trying to find that wire on a terminal board?

A. 109A55E

Assume that the value of R was chosen properly so the 6.2 volt Zener diode is operating I. The breakdown region. What is the voltage across a resistive load (RL) connected to the output of the voltage regulator if the value or RL is doubled?

A. 12.4 VDC

What voltages are available on the secondary of a 480^ (<—- this is a triangle) to a 480 Y?

A. 480 V phase to phase/230 V phase to neutral

What is the maximum pressure at which this system will operate?

A. 600 psi

AC voltmeters, unless marked otherwise, are calibrated to read out

A. Absolute average volts

On complex hydraulic circuits, pressure and flow adjustments are critical. The best way to set the control valves is to?

A. Ask the operators of the equipment what works best for you

A synchronous motor controller will start the motor as an induction motor then

A. Bring it to synchronization using DC excitation

When cylinder rods break repeatedly, the most obvious cause is?

A. Dirt has accumulated on the rod, scratching lines in it that allow stress concentrations to break the rod

In the circuit at left, what would happen if the center tap secondary transformer connection would break open at the transformer?

A. Lamp 3 would get brighter than Lamp 1

All 120V input/output devices that are to be used in DCS must be?

A. Local variable

In a DC shunt motor, interposes are positioned between the main shunt fields to armature could positioned between the main shunt fields to armature coil current. With the armature rotating clockwise in the sketch shown at left, what is the polarity of the interpole at P?

A. North

To display voltage values on a panel voltmeter of a high voltage power line (69 kV), what additional electrical equivalent meant should be added?

A. Potential transformer

A power distribution transformer uses secondary capacitors to improve the power factor of the system. If the breaker connecting the capacitors to the system tripped, the

A. Power to the load would decrease

A disadvantage of a dual line lubrication system is?

A. The system continues to operate should individual feeder valve block

When the transistor goes in the circuit at left is saturated,

A. The transistor acts like a short.

A hydraulic cylinder is fully extended when a machine is started up. Pilot-operated check valves keep the slinger from Moving while the machine is operating. When the machine gets hot, the cylinder cap seals are extruded and the cylinder ends leak. The most likely cause is?

A. Thermal expansion of the oil in the confined space of the cylinder.

In trouble-shooting a pneumatic system you should first?

A. Turn on the power

The digital component at left will produce a truth table as in

B. 0110

In the diagram at left, what would the ammeter reading at "A" equal?

B. 2 times that of B

Given the following program, what valued would be printed? 10 K=2 20 R=1 30 R=R * 2 40 K=K+2 50 IF (K<5) THEN GO TO 30 60 PRINT R 70 STOP

B. 4

When the probes of a voltage tester are placed across the energized 250 VDC circuit as shown at left and the tester reads 250 VDC, the?

B. Circuit is okay

A major problem with compressed air systems results from the?

B. Fact that this energy can't be stored

What all conveyors stopped, what happens when the "start" button of conveyor #2 is depressed momentarily in the diagram at left?

B. M2 runs momentarily

When checking for potential failure, a mechanic should check a gear reducer for?

B. Oil viscosity

When the synchronous speed of an induction AC motor decreases, the motor nameplate current usually is higher than for the same horsepower higher speed motor. This happens because the?

B. Power factor of the slower motor is lower

If 1 1R45 resistor opens, what would happen?

B. Process section would not speed up

Electrical contacts in a thermostat must be small and therefore chant handle the supply of current to a motor. The heavier current would be controlled through a ?

B. Relay

A current transformer rated 2000/5 means

B. The current transformer is rated for use in a 2000 volt circuit.

Modern AC motors are rated for 460/230 volts, 2 phase, 60 Hz. Normal plant distribution voltage is 480 volts. The main reason for this inequity is?

B. The motor you are looking at is an old design from when plant distribution voltage was 460 volts

Electrical bus bar connections must be inspected regularly for tightness because?

B. Thermal expansion differences in the conductor and fastener naturally loosen tight bolts

In the circuit at left, what would be the voltage at V out if the voltage at V were changed from 10 volts DC to 30 volts DC?

B. Volts stay the same

The commutator of a DC motor is made of copper and the brushes are carbon. With the motor running under normal conditions and at moderate load, the commutator will?

B. keep a bright polished light or dark brown appearance

If the contact or cook description is shown in lower case letters, then the coil and contact are?

B: local variable

The RMS (Root Mean Square) voltage of an AC since what is?

C. 1/2 peak to peak

USE THE ELECTRICAL ENGINEERING POCKET HANDBOOK According to the table, the maximum number of conductor of type TW, size 10 AWG that should be in a 1 inch intermediate metal conduit is?

C. 13

In the diagram at left, after an up transition has occurred on the go contact, the off-TMR coil will drop out in?

C. 2 min. 10 sec.

If a pressure gauge indicates a 34.7 psi g, what will a pressure gauge indicate on psia?

C. 34.7

How many input combinations exist for a three input logic device?

C. 8

One cycle of and one wave is displayed on an oscilloscope in horizontal distance of 6.25 cm. If the sweep time is 2 micro sec/cm, the frequency of the sine wave is?

C. 80 kHz

Which of the following input operations requires a conversion to digital form prior to input?

C. Contact closures

A potential transformer is used for

C. Fuse protection for overloads

Capacitive reactance is inversely proportional to?

C. Inductance and voltage

On large horizontal AC and DC motors, plane Babbitt bearings are needed to support the weight of the armature. The bearings are lubricated with oil rings. The oil rings

C. Must always rotate with the motor shaft, carrying oil to the bearing.

The purpose of a bypass valve around a pressure reducing valve is to ?

C. Offer less resistance to flow than bushings

The oil reservoir on a pressure compensated pump hydraulic system begins running much hotter than normal. Which of the following is the most likely course of the heat?

C. Pump pressure is set too low causing hydraulic motor to overheat

An oscilloscope is connected in the differential mode across an SCR (anode to cathode). A waveform is found as shown at left. The SCR is conducting during time

C. R+T

To properly turn off an SCR once it is conducting,

C. Reverse bias the anode with respect to the cathode

A 40% pressure drop across an oil filter screen indicated that the ?

C. Screen is dirty

Nonferrous nuts and bolts are used for high frequency heating conductor terminations because?

C. The ferrous fastener will melt

A question of efficiency is raised about a motor/reducer drive system. The 500 HP DC motor is operating at rated voltage, current and speed as measured with a tachometer, voltmeter, and ammeter. Neither component is excessively hot.

C. The motor is developing full horsepower, so the reducer must be running at low efficiency

An inexperienced electrician noticed that the secondary voltage on a 480 volts distribution transformer is 510 volts. He is concerned because one he checked last month was 461 volts. You explain to him that although both voltages are within the voltage tolerance established by NEMA,

C. The transformer reading 461 volts should be adjusted to get closer to 510 volts

The circuit at left has an input of +2 volts DC, what is the value of the output voltage

D. -20V

The power Siddons the 20 ohm resistor at left is?

D. 2000 watts

A single-phase transformer circuit feeds a motor and heating load of 50 kilowatts. At a power factor of .8, the KVA rating of the step down transformer would be?

D. 62.5 KVA

Which of the following will stop conduction once an SCR breaks into conduction?

D. Apply another pulse that is more negative than the original to the gate

Assume the system is functioning properly, with the operating valve in its normal position, the pump is then activated and the system pressure reaches 575 psi. The

D. Fluid from the rod end of the drill cylinder will discharge through the four-way valve into the reservoir

In the circuit at left is a typical power distribution schematic. The W, X, and Y units are used for?

D. Line voltage metering

EEPROM memory can be erased

D. Magnetically only

A regenerative solid state derive prevents a generating motor from ?

D. Over current

The derivative function when added to a proportional controller?

D. Responds to rate of change in the error signal