Help
Options
Didn't know it?
click below
click below
Knew it?
click below
click below
Don't Know
Remaining cards (0)
Know
retry
shuffle
restart
0:00
Embed Code - If you would like this activity on your web page, copy the script below and paste it into your web page.
Normal Size Small Size show me how
Normal Size Small Size show me how
Controls
Units 2 & 3
| Question | Answer |
|---|---|
| The heavier lines on electrical diagrams usually indicate the control circuit conductors | False |
| In a ladder diagram components are arranged according to their physical position in the installation | False |
| The conductors feeding to a large motor would be considered to be part of the control circuit | False |
| When more than one electrical load is connected in a rung of a ladder diagram, the loads are normally connected in series | False |
| Wires common to each other are usually identified by the same number | True |
| If a control circuit is supplied from a grounded circuit, it makes no difference what side of the line is grounded | False |
| Wiring diagrams are used when installing and tracing wires in electrical installations | True |
| With low-voltage protection, when power is restored after a power failure, manual restarting is required | True |
| No wires or components are normally shown on block diagrams | True |
| The direction of rotation of a DC motor depends on the direction of the magnetic field and the direction of the current flow through the armature | True |
| Motor terminal markings are usually used to tag only those terminals to which connections must be made from external circuits | True |
| Single-phase AC motors are typically constructed in small horsepower sizes | True |
| All 3-phase motors are wired so that the phases are connected in either Wye or Delta configuration | True |
| The rated nameplate speed of a motor is its approximate speed with no load applied | False |
| The motor nameplate Design letter is an indication of the motors torque speed curve | True |
| A motor with a low power factor rating will draw less current for the same horsepower than a motor with a high power factor | False |
| Two-wire control circuits are designed to protect against automatic restarting when power returns after a power failure | False |
| Ladder diagrams show | the electrical connections |
| The two basic parts of a typical motor circuit are the | control circuit and power circuit |
| On a ladder diagram, all wires that connect to a common point are assigned | the same numbers |
| Which of the following diagrams shows an electrical installation reduced to its simplest form | single-line diagram |
| In a dual-voltage split-phase motor, the two run windings are connected in ___ for the High voltage operation | series |
| When a split-phase motor is operated with a capacitor in series with one of the stator windings the | starting torque is higher |
| The speed of an AC induction motor depends on the | voltage of the electrical power supply and number of poles built into the motor |
| NEMA requires that the motor be able to carry their rated horsepower at nameplate voltage plus or minus | 10% |
| Standard NEMA motor insulation classes are given by | alphabetic classification |
| A motor nameplate indicates that the motor has a "service factor" of 1.25. This means that the | motor can on occasion safely develop 125% of its HP |
| The nameplate of a motor indicates that its thermal protected. This means | the motor has a built in thermal device |
| The plugging of a motor refers to | braking by reverse rotation |
| With "low voltage protection" motor control is | a power failure disconnects service and when power is restored manual restarting is required |
| Which of thhe following types of motor starters connects the motor directly to the supply line on starting? | full voltage starter |
| Two-wired control circuits use a ___-contact type of control device | maintained |
| A ladder diagram is a _____ representation of an electric circuit | schematic |
| On electrical diagrams, conductors that cross each other and make contact are represented by a heavy ___ at the junction | dot |
| For a ____ connection of loads, the voltage across load is the same as that of the applied voltage | parallel |
| On a ladder diagram, a line is defined as a complete ___ from L1 to L2 that contains a load | path |
| A wiring diagram is intended to show the actual ____ of all components | location |
| Industrial applications use DC motors because the ___/____ relationship can be easily varied | speed/torque |
| The rotating part of an AC motor is referred to as the ___; the stationary part is called the ____ | rotor, stator |
| The phase rating of a motor is listed on the nameplate as ___,____,____ | DC, 1-phase, 3-phase |
| The amount the motor winding temperature will increase above the ambient at full load is specified according to the nameplate _______ rating | temperature rise |
| The two general classifications of motor enclosures are ____and ____ | open, totally enclosed |
| Single-phase power is usually supplied to an industrial customer | False |
| The higher the level of the distribution voltage, the more difficult and expensive it becomes to safely insulate between line wires, as well as from line wires to ground | True |
| The switchboard is usually supplied from the panelboard | False |
| Movement of the coils within a transformer produces the transformation of voltage | False |
| For an ideal transformer, the power input is equal to the power output | True |
| The voltage ratio of a transformer is equal to its turns ratio | True |
| If the secondary circuit of a transformer becomes overloaded, the primary circuit will not be affected | False |
| A transformer has subtractive polarity when terminal H1 is adjacent to terminal x1 | True |
| In a Delta-connected transformer, the phase and line voltages are equal | True |
| Instrument transformers provide insulation between the instrument and the high voltage of the power circuit | True |
| High voltages are used in transmission lines to reduce the transmission ____ | current |
| For a given amount of power delivered, doubling the transmission voltage cuts the electrical loses by ___ | 75% |
| A unit substation of a building contains | high-voltage switch gear, low voltage distribution devices, transformer |
| Conduit conductor capacity is generally based on a ___ fill ratio | 40% |
| The transformer winding coil that delivers power to the load is known as the ___ coil | secondary |
| The principle of operation of a transformer is based on ___ induction | mutual |
| The efficiency of a transformer is typically in the ___ range | 90% |
| The low-voltage windings leads on a single-phase transformer are marked | X1 and X2 |
| Three-phase transformers are normally connected in ___ or ___ | Wye Delta |
| If the phase-to-neutral voltage is 120 volts in a Wye transformer system the phase-to-phase voltage would be | 208v |
| Compared to an equivalent traditional transformer the autotransformer is | lower in cost, smaller in size, lower in weight |
| The secondary winding of a current transformer is designed to produce a standard current of | 5A |
| Current transformers are used to | supply a small amount of current that is proportional to the main current |
Created by:
jairoandres90
Popular Engineering sets