Electrical Flashcards
How are the limits powered
Series
What is the percent of air in a low fire start
40 percent or less of rated max input
What BTU needs a low fire start provin
1,000,000 BTU
What do parallel position systems use
Potentiometer
Can you adjust the over travel proof of travel switch
No it is factory set
What are the common terminals on a 24 V transformer
C and R
What is an isolation transformer
Has two isolated circuits
Number of wraps decides voltages
Help removed electrical noise
What amount can the inrush be more than the steady VA
3-10 times
Can last 30-50 milliseconds
Inrush Va equation
whole equation square rooted
total inrush squared multiplied by total sealed squared
What is the typical sparker gap
1/8 - 5/32
What happens if the sparker gap is wrong
Wont light
Or shortens life of the sparker coil
How many ignition electrodes does the oil need
2
Auto transformers
Use same windings for primary and secondary
Enable start in squirrel cage motors
Uses reduced starting current
Metel ranges for RTD
Copper - 200-260
Nickle - 90 to 260
Platinum - 200-850
3 different ways RTD wiring is done
Wire round
Coil element
Thin film RTD
How is wire round set to 0 degrees
Wire is trimmed
Is Wire round recommended for industrail?
No it is accurate but fragile
Properties of wire round RTD
Has a wire round a non conductive materials
Properties of coil element RTD
Wires rolled into small coils then but loosely at the end with powder
Free to expand
powder increases rate of heat
Most common in industrial
Properties of thin film RTD
Cheapest
Fastest response time
Thin platinum pathways in ceramic base
Not as accurate because it can self heat
When would you use a two wire sensor
When accuracy is not critical
What does a pressure transducer do
Coverts pressure into an electrical signal
What do biomass and O2 sensors do
Monitors unused gas and adjusts fuel gas mixture accordingly
What is a device connected to a network called
Node
What is a gateway
Adds an access point between 2 networks
How to determine full load amps
Get FLA off name plate
multiply bu 1.25
use table 37 and 75 degrees
Size magnetic starter
Find HP on rating plate
Use Nema sizing chart for controller size
Must be more or equal to FLA
Size starter overload
Find full load current (amps) and service factor
If 1.5 use 125% if less use 115% (multiply by it)
Size disconnect fuses
Table 29 (Usually 175%)
FLC amps multiplied by number determined above
How to size wires
(to branch circuit, disconnect, overload, fuses)
Use table 2 to size wire
What is a wire
Single conductor
What is a cable
Group of wires in an insulated conductor
Standard vs solid
Standard is more flexible
Solid is less resistant
What is a mag starter
Electrical switch that is a safe way to start the motor
What is the Proportional in a PID
How fast you get to set point
What is the integral in a PID
Uses previous data to put on the brakes or speed it up
What is the derivative in a PID
Stores the information for future
(Not used on a burner)
3 types of parameters for a VFD
Tunable on the fly- Can be adjusted when running
Configurable- only adjustable when unit is off
Read only- Cannot be adjusted
What does an ECC do
Transfers torque between two shafts without touching
Magnet on the drive
Non magnetic on the driven (Coupling)
