Transformes Test?

For a 7% impedance transformer over 1000 Volts without coordinated thermal overload protection, in a supervised location, a primary fuse would be sized at _______ without secondary protection.

250%

For autotransformers when the current is less than ______ , an overcorrect protective device shall be treated at not more than 167% of the input current.

9 amps

Fully rated systems consist of __________________.

Fuses Only Fuses and Breakers Breakers Only

The power rating of a single coil autotransformer is _______ the rating of the individual winding equivalent two winding transformer.

Higher than

What limits inrush current and reduces notching?

Reactors

What are some common applications in the use of autotransformers?

Reduced voltage motor starting Voltage regulators Variable Transformers

For existing installations, series ratings are permitted only if the series rated system combinations are _____?

Selected under engineering supervision and selection must be documented and stamped by a professional engineer. In addition, there series combinations must be marked on the equipment.

For a ______ application the source is applied across the entire coil, which acts as the primary

step down

For transformers 1000 Volts or less with primary currents of 9 amps or more, secondary not required if primary protection is provided at ______ percent or the next higher standard size.

125

A _______ can also be made from a two winding transformer by connecting the two windings something something continuous winding

Auto Transformer

When determining the proper wiring connections to develop a particular voltage, a technical knowledge of the _______

Available source voltage Type of Buck boost transformer available Desired output voltage

T/F A two winding transformer wired as an autotransformer can deliver more power than wired as a two winding transformer

True

T/F For transformers 1,000 volts or less, the secondary overcurrent protection device can be split up to six devices, provided the sum of the ratings does not exceed that of the single device

True

T/F In a buck boost transformer, the voltage across the primary should never be allowed to exceed the voltage of the coils

True

T/F Isolation transformers provide reactive control of current harmonics for both AC and DC

True

T/F Proper grounding practices along with drive isolation transformers are used to reduce common mode noise

True

T/F Transformers normally contain two independent circuits, the primary and the secondary

True

T/F Autotransformers share part of the windings between the primary and the secondary

True

A _________ transformer is a continuously adjustable autotransformer consisting of a single layer wound on a toroidal core, and a carbon brush that traverses this winding.

Variable

The OCPD must have characteristics such that under fault conditions, the short circuit current by the OCPD oscar mike less than the shortchanged circuit current ______ rating of the component or assembly protected.

Withstand

What type of transformer is not permitted to be installed on the load side of any system connection.

Zig Zag

T/F Oil immersed reactors are common in low voltage applications

False

What can be used to boost the voltage at the end of long lines where voltage is low during periods?

Buck boost transformer

Determining the what and calculating the required size of a buck boost transformer is a common method for sizing a transformer?

Load power Load current and buck or boost voltage

What type of reactors are placed in tanks and require a magnetic shield to prevent eddy currents from getting in the tank?

Oil Immersed

What type of reactors have a tendency to overheat due to the harmonic content of the output waveform?

Output

During a fault condition with an open circuit on the secondary side, anyone coming in contact with secondary may be exposed to the full _______ voltage.

Primary

T/F A fully rated system can consist of fuses only, circuit breakers only or combinations of fuses and circuit breakers.

True

T/F A reactor with about 3% impedance has the ability to reduce the notch depth by approximately something....

True

For a transformer 1000 Volts or less, with secondary current of 5 amperes, the secondary overcorrect protective device could be sized up to _______ of the transformer. Rated current where both primary and secondary protection is provided.

167%

A fault of a circuit in a system which is not selectively coordinated can result in an event referred to as _______.

Cascading

What is defined in the NEC as "Localization of an overcurrent condition to restrict outages to the circuit or equipment affected, accomplished by the selection and installation of overcorrect protective devices and their ratings or settings for the full range of available overcurrents, from overload to the maximum available fault current, and for the full range of overcorrect protective device opening times associated with those overcurrents.

Coordination, Selective (Selective Coordination)

Grounding the secondary of a drive isolation is beneficial because it _________.

Decreases common mode noise coupling from primary to secondary Supplies greater transient and impulse protection to the load side of the transformer Hinders induced ground current from moving upstream into the primary system

If the drive transformer has an ungrounded secondary, or if a high resistance ground system what what may be beneficial?

Electrostatic shield

Buck boost transformers should be used to correct a voltage drop when the load fluctuates

False

T/F For a new system installation, it is permissible to use a series rated combination even though evidence the panel board manufacturer has the panel board listed and marked for specific of OCPD.

False

T/F The impedance of an autotransformer is higher than the impedance of two winding transformer

False

Series rated systems do not consist of __________.

Fuses Only

The National Electrical Code® (NEC) requirements found in Section 450.3 are for the protection of ? .

The Windings of the Transformer Only

T/F With the secondary grounded, a transformer wired as a separately derived system acts as a transfer of common mode noise and transients from primary source to the drive

True