1The voltage produced in a transformer is directly proportional to what?
Number of turns on the primary and secondary
2THe current a transformer can handle is inversely proportional to what?
Number of turns
3What is an isolation transformer?
A transformer with a secondary with no potential to ground
4What is a center tap?
A tap in the middle of a winding to produce some fraction of the voltage of the complete output or input
5How do you determine the current capacity of a normal standard transformer?
Divide the VA rating by the voltage on each side
6A standard transformer rated at 200 VA can handle how much current on the primary side if the primary voltage is 100 volts and the secondary voltage is 50 volts?
2 amps primary and 4 amps secondary
7How much secondary current can a 500KVA transformer handle if the primary voltage is 250 volts and the secondary side is 125 volts?
4000 amps
8How does an autotransformer vary from a standard transformer?
The secondary side has potention to ground, and it can handle high currents
9What is the advantage of an autotransformer over a standard transformer as far as surrent is concerned?
It can handle higher currents
10What is the one hazard when using auto transformers?
The potential to ground on the secondary side
11What is a "buck and boots" transformer used for?
To raise or lower voltage from 240 volts to 208V
12If you had an oven rated at 240 volts and only had a 208 volt supply available, what kind of transformer would be used to raise the voltage?
Buck and boost
13The majority of transformer failures are due to what?
Overloads and shorted loads
14When you replace a transformer and are unable to locate the reason for the failure of the original unit, what else should you install?
A fuse in either the primary or secondary side
15What kind of fuse should be used to protect transformer circuits?
Fast blow
16What are some of the reasons that transformers fail?
Enviornment, overloads, shorted loads
17If you have a transformer rated at 250 VA, the primary voltage is 250 volts, and the secondary voltage is 125 volts, what size fuse should be used to protect the circuit?
One amp on the primary side or 2 amps on the secondary side
18If you have a transformer rated at 500 KVA, the primary voltage is 250 volts, and the secondary is 120 volts, what size fuse should be used to protect the circuit?
2000 amps on the primary side or 4000 amps on the secondary side
19Whenever you are checking the output voltage of a transformer, always make sure the transformer is connected to what?
The load
20If a transformer puts out a certain voltage with no load, but the voltage disappears when the load is connected, what is the problem?
A shorted load and maybe a bad transformer if the short permanently damaged the transformer