ECT RT3 Test Flashcards
Resistors in parallel, what happens to current, if one of the resistors opens?
Resistors in parallel, current will drop off for what reason?
Resistors in series, if the resistance increases, what happens to the voltage on the next?
Resistors in series, the voltage will decrease on the neighboring resistor, if what happens to the first?
Resistors in series, what happens to the voltage on a resistor if the resistance increases?
Resistors in series, the voltage on a resistor will increase when what happens to the resistance?
Resistors in series, what happens to the amperage if one resistor increases resistance?
Resistors in series, amperage, will decrease if this happens?
What are the requirements for a circuit?
A power source plus a complete circuit equals?
How much higher is inrush current compared to seal in current?
What is 10 to 12 times higher than seal in current?
What eliminates chatter?
What do shading rings do? 
What causes chatter?
Oscillation of current caused by a sign wave, trying to hold a contactor closed 
Power loss in the form of heat is caused by what?
What effect does eddy currents have on a circuit?
Inductive proximity sensors are used to detect what type of material?
What type of proximity sensor should you use to detect metal?
What type of material can capacitive proximity sensors sense?
What sensor should you use to detect all types of materials?
The on and off points of an inductive proximity sensor is called what? It prevents chattering.
Hysteresis is determined by what and what is it used for? 
What is the range of photo detectors?
What can detect a target at a distance between 5 mm to over 250 m? 
Transmitted beam photo detectors are set up how?
What detector has both a light source and a receiver?
What has the longest sensing distance and highest operating margin?
Can transmitted beam cutter detectors, be used for long distances, or short distances?
How are retro Reflective photo detectors set up?
What photo detector uses a reflector?
How is a diffuse photo detector set up?
What photodetector does not need a receiver or reflector?
What does light operate mode mean?
What type of photo detector is on when it sees itself?
What does dark operate mode mean?
What type of photo detector is on when it does not see itself?
What type of detector has an inherent blind zone at the sensing face?
What is the problem with ultrasonic proximity sensors?
Which sensor would you probably use to see 25 m? To see longer distances.
When are you most likely to use an ultrasonic proximity sensor?
Is an overload confined to normal circuit paths?
when an overcurrent is confined to normal circuit paths, is that an overload or a short circuit? 
Is a short circuit confined to normal circuit pass
When an overcurrent is not confined to a normal circuit pass, is that an overload or short circuit?
An overload is how many times greater than normal current?
What is 1 to 6 times greater than normal current?
Short circuit current is how many times greater than normal current?
What is hundreds of times greater than normal current?
Interrupting rating is the maximum value of what that a fuse can safely handle?
The maximum amount of current a fuse can safely handle is called what?
If a fuse operates quickly, What is it called?
A current limiting fuse does what?
Which type of fuse works best for branch circuit protection?
K5 types fuses work best for what production?
What class of fuse works best for motor circuits?
RK five fuses work best for what type of circuit?
What type of fuse works best for arc flash energy reduction?
J type uses work best for what type of circuit?
What type of fuse works best for small motors?
Cc fuses work best for what type of circuit?
It’s a fuse has a large amount of damage. Is that a short circuit or an overload?
Short will produce what type of damage to a fuse?
If there’s only a small break in a fuse, is that caused by a short circuit or an overload?
An overload will produce what type of damage to a fuse?
Which circuit breaker is best suited for overload protection?
A thermal circuit breaker is best suited for what type of protection?
What advantage does a circuit breaker have compared to a fuse?
Breakers can be used as a switching device
Which circuit breaker is best suited for high temperature areas?
Ambient compensation circuit breaker is best used in what cases?
Magnetic circuit breakers protect against what?
What circuit breaker provides instantaneous action against shorts?
Which circuit breaker provides protection against extended overcurrent?
Thermal circuit breakers provide what type of protection?
What is interrupting capacity for a circuit breaker?
How much current a breaker can interrupt without damage to itself is defined as what?
Using laminated steel in contactors, has what benefit?
What is used to reduce eddy current?
Which type of proximity switch has a probe at its face?
A capacity proximity switch has what type of sensor at its face?
Which type of proximity switch has a coil at its face?
An inductive proximity switch has what type of sensor at its face?
What is used as a light source in a photo detector?
An LED is used for what purpose in a photo detector?
How do on delay timers work?
What type of delay timer is this? Circuit closes if the power remains on after the timer has ended. Timer starts with the power is on. 
How do off delay timers work?
What type of delay timer is this? Circuit is closed when power comes on, and remains closed until power is off, and the timer ends. Timer starts when the power is off. 
Tripping current is how much of actual dial adjustment?
What is 125% of dial adjustment on an overload relay?
K fuses are not good for motors or inductive loads for what reason?
K fuses have no time delay and are good for what in what type of circuits?
Rk fuses are used for motors and inductive loads for what reason?
Rk fuses are good for what type of circuits because they have a time delay?
Overload relays are used to protect motors from what?
 What would be used to protect a motor from prolong overload, phase unbalance, or phase loss? 
Which circuit breaker protects against a short?
A magnetic circuit breaker protects against what? 
Which circuit breaker protects against overcurrent?
A thermal circuit breaker protects against what?
Motor rotation speed?
7200 rpm / # of poles
1HP = ? W
1HP = 746W
Or an asynchronous (induction) motor how is slip define?
What is the difference between rotor speed and synchronous speed?
Current instantaneous =
Current max times sign of angle
Xl =
2 pi f L
Zt = hypotenuse
Rt and Xl legs
Power factor =
Cosine of angle theta
VA =
Apparent power (S)
VARS =
Reactive power (Q)
Formula
Q reactive (VARS) =
Vt * It * sin Theda t
Formula
P real (watts) =
Vt * It * cos Theda t
Formula:
S apparent =
Vt * It
Three phase
P real =
Square root of three
* Vl * IL * cos Theda
Three phase
Q reactive =
Square root of three
* Vl * IL * sin Theda
Three phase
S apparent =
Square root of three
* Vl * IL
Three phase delta
Vl = Vph
IL = ,/3 * Iph
Three phase Wye
IL = Iph
Vl = ,/3 * Vph
