In the circuit shown in the figure above, what prevents motor #2 from starting before motor #1?

Two circuits that employ a control relay to provide jogging are shown in the accompanying figure. In both these circuits the control relay provides the ____________________ contacts, not the M starter.

In the circuit shown, when the forward jog push button is pressed, the normally open section makes connection and provides power to ____________________.

The figure shows the components needed to construct a(n) ____________________ control circuit

In the accompanying figure, when the START button is pressed, motor starter coil M energizes and __________ all M contacts. The three M load contacts connect the motor and resistors to the line.

In the figure below, the START button acts as both the START and jog button for the circuit. A(n) ____________________ can be used to provide the same basic type control.

In the circuit shown in the accompanying figure, motor #3 starts five seconds after motor #____________________ starts.

In the accompanying figure, both overload relays are connected in series so that an overload on either relay will ___________ both motor windings.

The accompanying figure shows transformers connected in open-____________________.

In the circuit shown in the accompanying figure, timer coil TR1 is connected in ____________________ with the 1M starter coil.

Normally closed F and R auxiliary contacts are used to provide ____________ for the forward-reverse control.

The accompanying diagram uses ____________________ to shunt the resistors out of the circuit after some period of time.

The circuit shown in the accompanying figure permits ____________________ motors to start in sequence.

This figure shows stator windings that are connected in _________ during the starting period.

In the figure, the dashed lines drawn between the push buttons indicate that they are ____________________ connected.

Using the given schematic. When the STOP button is pressed, the three motors will stop in sequence from #3 to #1 with a time delay of five seconds between each motor. ___________ will stop immediately. Five seconds later motor #2 will stop, and five seconds after motor #2 stops, motor #1 will stop.

The accompanying figure shows a bellows-operated ____________________ timer.

In the circuit shown in the accompanying figure, the current sensor contacts are normally open.

Based on the accompanying figure, when the STOP button is pressed, all CR contacts open immediately.

Sequence control can be achieved by several methods.

In an inductive circuit, the current must rise at an exponential rate.

Many autotransformer starters contain taps that can be set for 50, 65, or 80 percent of the line voltage.

Across-the-line starting is the simplest of all starting methods.

When dual voltage motors are used, the motor must be operated on the high voltage setting of the motor.

Jogging can be accomplished using a double-acting push button.

A control relay is used to provide jogging in one direction only.

Dual voltage motors designed for wye-delta starting will supply all 12 T leads at the terminal connection box.

Across-the-line starting is only used for alternating current.

Dual voltage motors not intended for wye-delta connection will have certain terminals tied internally.

Direct current motors depend on inductive reactance to limit current flow.

Open transition starting means that the motor is connected to the power line during the transition from wye to delta.

For closed transition starting, four separate start contactors are used.

A selector switch is used to break the connection to the holding contacts.

The on-delay relay is often referred to as DODO.

One of the methods of electrical interlocking is accomplished with the use of double-acting push buttons.

Most autotransformer starters use two transformers to reduce the voltage applied to the motor during the period of acceleration.

Delta connected dual voltage motors are acceptable for part winding starting.

The motor is connected to the power line regardless of which direction it operates.

One way of determining when to shunt the resistors out of the circuit is by sensing motor current.

The type of bars used to construct the rotor has a great effect on the operating characteristics of the motor.

Pneumatic timers are adjustable over a wide range of time periods.

Pneumatic timers are affected by variations in ambient temperature or atmospheric pressure.

Most ladder diagrams show coils connected in parallel.

Resistors connected in series with the motor limit the amount of in-rush current.

Wound rotor type motors and synchronous motors generally use autotransformer starters.

Part winding starting is typically used for motors that supply the moving force for centrifugal pumps, fans, and blowers.

If R coil energizes, all R contacts change position.

In a resistive circuit, the current will take some time to reach its full Ohm’s law value.

In a wye connection, the line current and phase current are not the same.

The on-delay relay is often referred to as DODO.

Circuits that permit the automatic starting of motors in sequence are rare.

Part winding starters provide closed transition starting.

You can obtain jogging control with the use of a selector switch.

Clock timers are generally used to operate several switches.

Autotransformer starters provide greater starting torque per ampere drawn from the line than any other type of reduced voltage starter.

In a circuit in which three motors turn off in sequence, an overload on any one motor will not have an effect on the other motors.

Instantaneous contacts change their positions immediately when the coil is energized and change back to their normal positions immediately when the coil is de-energized.

Closed transition starting does not disconnect the motor from the power line.

In part winding starting, neither of the two windings is individually capable of withstanding the starting current for more than a few seconds.

Contactors intended to connect direct current motors to the line often have arc suppression and magnetic blowout coils.

Four methods of electrical interlocking are available.

Most reversing controllers only contain mechanical interlocks.

The abbreviations TO and ____________________ are used with some control schematics to indicate a time-operated contact.

Motors that are intended to operate on two voltages such as 240 or 480 volts contain two separate ____________________ of each phase.

In a DC contactor with two coils, the ____________________ coil is intended for momentary duty and not continuous operation.

Open transition simply means that there is a brief period of time when the motor is ________________ from power when the start contactor opens and the run contactor closes.

Because push buttons employ a __________ to return the contact to their normal position, if a person’s finger slips off the jog button, it is possible for the spring to reestablish connection with the normally closed contacts before the holding contact has time to reopen. This would cause the motor to continue running instead of stopping. In some cases, this could become a significant safety hazard.

Sequence control is used by such machines as __________ presses that must have a high pressure pump operating before they can be used, or by air conditioning systems that require that the blower be in operation before the compressor starts.

The method of starting in which only half the motor winding is used during starting is called ____________________ starting.

Resistor starting and ________ starting are the two methods of reducing the amount of starting current.

In closed transition starting, the CTs reduce the current to a level that common ___________ heaters can be used to protect the motor.

What happens if the second winding is not connected to the _____ line within a short period of time? The first winding can be severely damaged.

In cam timers, the operation of the switches is controlled by the action of adjustable cams attached to a common shaft. The shaft is turned by a small __________ motor.

Direct current motors require only one ____________________ contact to connect or disconnect them to the power line and one overload sensing device.

To jog the motor, simply hold down the _________ button and jog the circuit by pressing the START button. To run the motor, release the STOP button and press the START button.

Small DC motors can be started across-the-line because they have low __________ and the armature will rapidly gain enough speed to produce the counter EMF needed to limit current.

____________________ starters are generally employed to start squirrel cage type motors.

One advantage of part winding starters is that they provide ____________________ starting because the motor is never disconnected from the power line during the starting time.

With part winding starting, the first winding will ____________________ rapidly if the second windings is not connected within a very short period of time.

If 50 percent of the normal voltage is connected to the motor, the in-rush current will drop to ____________________ percent.

Cam times are also known as ____________________ timers.

The two conditionswhere it is not possible to start a motor across-the-line are excessive starting current and excessive ________.

Current ____________________ are used to sense the amount of motor current.

The two general classifications in which time delay relays can be divided are the on-delay relay and the _________ relay.

Some circuit requirements may demand that the motors turn off in sequence. This circuit requires the use of _________ timers. Also, a control relay with four contacts is needed.

In ___________ sequence control circuits which sense motor current, when the current of a motor drops to a predetermined level, it permits the next motor to start.

The stator windings may be wye or delta connected depending on the ____________.

How many poles per phase does a sychronous three-phase motor operating at 3600 RPM have that is connected to 60Hz?

The addition of two ____________________ make it possible to start motors in sequence from #1 to #3 with a time delay between the starting of each motor as well as stopping the motors in sequence from #3 to #1 with a time delay between the stopping of each motor.

Open transition starting is generally used on starters of size ____________________ and smaller.

Having both contactors energized would result in two of the three phase lines being _______ together.

In an autotransformer starter, when the START button is pressed a circuit is completed to the __________ of control relay CR, causing all CR contacts to close.

To help prevent damaging the first winding, some circuits contain a timer that disconnects power to the motor if the second winding is not energized within a predetermined time. This timer is often called a(n) ____________________.

The term jogging means to start a motor with short jabs of power at full voltage. The term inching means to start a motor with short jabs of power at _________ voltage.

Some control circuits sense ____________________ speed to determine when to shunt the resistors out of the power line.

Wye-delta starting is accomplished by connecting the stator windings in ________ during the starting period and then reconnecting them in delta for normal run operation.

Autotransformer starters reduce the amount of in-rush current by reducing the _________ applied to the motor during the starting period.

Some resistor and reactor starters use multiple steps of starting. This is accomplished by ___________ the resistor or reactor to produce different values of resistance or inductive reactance.

____________________ is accomplished by connecting resistors in series with the motor during the starting period.

In-rush current is referred to a(n) ____________________ current.

Reducing the voltage applied to the motor __________ the amount of in-rush current and reduces the motor torque.

If the stator windings are connected in ____________________, the voltage across each phase will be 480 volts because line voltage and phase voltage are the same in a(n) ____________________ connection.

The type of rotor is identified by a code letter on the ____________________ of a motor.

Reactors limit in-rush current with ____________________ instead of resistance.

In a schematic diagram, mechanical ________ are shown as dashed lines from each coil joining at a solid line.

What is the synchronous speed of a three-phase motor that contains 9 poles per phase and is connected to 60Hz?

Timer relays are similar to other control relays in that they use a(n) ____________________ to control the operation of some number of contacts.

Each winding in motors designed for part winding starting is individually protected by ____________________ overload heaters.

In a grounded system, the current sensing device must be in the ____________________ conductor.

The two requirements that must be met before wye-delta starting can be used are:

1) The motor must be designed for the stator windings to be connected in delta during the run period.

2) All ________ windings leads must be accessible.

Electrical interlocking can be accomplished by connecting the normally closed ____________________ contacts on one contactor in series with the coil of the other contactor.

The most critical part of connecting a wye-delta starter is making the actual ______ connections to the motor.

The addition of a(n) ____________________ to the jog circuit eliminates the problem of the holding contacts making connection before the normally closed section of the jog push button makes connection.

____________________ forces motors to start or stop in a predetermined order.

Clock timers use a small AC ____________________ motor similar to the motor found in a wall clock to provide the time measurement for the timer.

___________ can be used to reduce the amount of voltage applied to the motor during inching, or reactors or resistors can be connected in series with the motor to reduce the current supplied by the power line.

Wye-delta starting is sometimes called ____________________ starting.

Mechanical interlocking is accomplished by a using the contactors to operate a mechanical lever that prevents the other contactor from ________ while one is energized.

Some electronic timers use an _____ time constant to obtain the time base and others use quartz clocks as the time base.

Inching control requires the use of a separate ____________________ because the power supplied to the motor must be separate from full line voltage.

Time delay is one of the most popular methods of determining when to connect the motor directly to the __________ because it is simple and inexpensive.

Pneumatic timers operate by restricting the flow of _____ through an orifice to a rubber bellows or diaphragm.

The direction of rotation of any three phase motors can be reversed by changing any two motor ____ leads.

Wye-delta starting is often used with large horsepower motors to reduce in-rush current during the starting period and reduce starting ____________________.

Initial in-rush current is limited by the ___________ of the windings. When the armature begins to turn, counter EMF is developed in the armature. Counter EMF is the main current limiting force in a direct current motor.

Interlocking prevents some ________ from taking place until some other action has been performed.

Across-the-line starting is accomplished by connecting the motor _________ to the power line.

Autotransformer starters are ____________________ type loads and will affect the power factor during the starting period.

Magnetic reversing starters generally change T leads 1 and ___ to reverse the motor.

If the stator windings of a motor are connected in delta during the starting period, the starting current will be ____________________ times the value if the windings were connected in wye.

It is possible to provide a third step in the starting process and further limit starting current. This is accomplished by connecting resistance in ________ with the stator winding during the starting period.

Direct current starters and contactors that do not utilize arc suppressors or magnetic blowout coils often use multiple contacts to break the circuit. Connecting contacts in ________ gives the contactor the ability to break higher voltages.