Chapter 7 Test 8 Flashcards
A small air gap is left in the iron core amateur circuit to __________.
prevent the amateur from staying in a sealed position
A(n) __________ is the number of locations within the valve in which the spool is placed to direct fluid through the valve.
position
Voltage should be at least __________ % of a solenoid’s rated valve.
85
Without the __________, excessive noise, wear, and heat buildup on the amateur faces.
shading coil
__________ magnets are magnets that can retain their magnetism after a magnetizing force haas been removed.
Permanent
__________ magnets are magnets that have extreme difficulty in retaining any magnetizing after the magnetizing force has been removed.
Temporary
A burned out solenoid is normally evident by __________.
pungent odor cause by bunt insulation.
A DC generator always has a(n) __________ armature and __________ field windings.
rotating a stationary
The __________ is the relationship between the current in a conductor and the magnetic field existing around the conductor.
left hand generator rule
The output voltage of a shunt-wound generator may be controlled by means of a(n) __________ connected in series with the shunt field.
rheostat
The __________ theory of magnetism states that all substances are made up of an infinite number of molecular magnets.
molecular
A(n) ___________ is an electric output device that converts electrical energy into a linear mechanical force.
solenoid
The __________ is used to determine the direction of motion of a current-carrying conductor in a magnetic field.
electron flow motor rule
__________ is unwanted current induced in tthe metal structure of a device.
Eddy Current
A(n) ___________ is a single turn of conducting material mounted on the face of the magnetic laminate assembly or armature.
shading coil
The mechanical life of most coils is improved by encapsulating them in a(n) ___________ or a glass-reinforced alkyd material.
epoxy resin
__________ voltage is the minimum control voltage which causes the armature to start to move.
Pick-up
__________ voltage is the voltage that exists when voltage is reduced sufficiently to allow the solenoid to open.
Drop-out
Manufacturers provide letter or __________ codes to indicate the voltages available for a given solenoid.
number
__________, two-way valves are common in refrigeration equipment.
Direct-acting
DC series motors can develop __________ % of full-load torque upon starting.
up to 500
A solenoid __________ when the voltage is excessive.
overheats
__________ voltages may damage the insulation on the solenoid coil.
Transient
No movement of the needle on an analog meter or infinite resistance on a(n) __________ set to measure resistance indicates the coil is open and defective.
DMM
__________ valves are used as shutoff, check, or quick-exhaust valves.
Two-way
A(n) ___________ circuit is a circuit in which current leaves its normal path and travels to the frame of the motor.
grounded
A(n) __________ motor is used when high starting torque and constant speed are required.
DC compound
A(n) __________ connects a brush to the external circuit of a DC motor.
pigtail
The strength of an electromagnet can be increased by __________.
increasing the voltage
increasing the number of coils
inserting an iron core through the coil
