First Half Second Semester Flashcards
Voltage for control
+/- 0-10v DC
Taper lock bushing
What connects to sprocket
Oscilloscope
Visual volt meter
Can read ac/dc signal
Needs iso transformer
1hz = 1 cycle
Motor design in hoist
Designed to prevent loss of directional control while reversing motor
-rules out use of single Phase motor
How much of cable sits in groove?
2/3rd of cable
Safety Relay
Heater, 2 contactor, reversible mechanical interlock w/ contactor
How many connections on potentiometers?
3 connections
2 sources of DC
3 parts of deck track
Knife
Dog
Receiver
Knife fits in dog
Receiver receives knife as it fits through dog
Alternative to load securing device
40:1 gearbox
Safety functions for hoists
E stop
Ultimate (over travel) limit switches
End of travel (initial, normal) limit switch
Signal from drive to motor
+/- 0-180v DC
+/- determines direction
VFD Path
AC -> Bridge rectifier -> DC -> DC Filter (capacitor smoothes out signal) -> high power transistor (high amperage)
Only works on polyphase motor! Needs self-starting, single Phase not self starting!
Spacing b/t grooves
Half of 1/16th
What doesn’t ESTA apply to?
Flying systems, chain motors, manual powered hoists
Why we use uni power drive?
Cheaper than buying bipolar drive
Grommet
Cable that wraps around turntable
of LSD in hoist
Should have at least 2 load securing device
Peak load
Abnormal situations/operations
FAT
Field accepted test
What carries load in power screw drive?
The nut
Technical spaces
Where the general public can’t get access
Enabling device
Someone with line of sight holds a button
Category 2 Stop
Machines decelerates to stop, power remains
Category 1 Stop
Machine decelerates to stop, then power removed
Competent Person
Authorized to take corrective measures to eliminate hazards
5-8 risk value
Acceptable only if risk is as low as is reasonably practicable
1-4 Risk value
Acceptable risk
How get +/- 0-10v?
Use variable resistor to control speed
Drawbar
Force to move the wagon
Assume 10-15% of load to move it
9-25 Risk Value
Unacceptable risk
Encoders generate
Pulses
Load carrying device
Connects b/t load and lifting media
Clamp
Truss
SAT
Shop accepted test
Minimum tensile strength of Lifting media
5x characteristic load
8x static load
1.33x peak load
A2D
Analog-to-Digital card
Takes analog signal, turns it digital so we can use it with PLC, Computer
Card needs 24 volts for card to work
Cable to shackle
Size up 1 size from cable to shackle
1/8” cable, 1/4” shackle
VFD limitations
Cannot work on single Phase ac motor, can’t vary speed
-has be 3 Phase motor
Characteristic load
Normal operations
Positive break operation
Can’t rely on springs to break connection
Category 0 stop
Uncontrolled stop caused by immediate removal of power
Should not cause permanent deformation or failure of any component of system
Variable Resistor
Resistor that has a movable unit
Pointing left, 10 volts
Pointing down, 5 volts
Pointing right, 0 volts
Load securing device can be a ____
A brake
What is diode
Diode is a semiconductor device
2 types of brakes
Load Brake: mounted on the drum
Motor brake: mounted on the motor
Lifting media
Wire rope
Chain
What is used to hoist
Qualified Person
Person with degree, or professional knowledge and training, that can solve problems related to subject matter and work
Digital value formula
(Volts • 256)/10 volts
2 parts of diode
Anode +
Cathode -
Background color estop
Yellow
Half wave rectification
Diode can block top or bottom half of alternating current
Use multimeter to measure
Resistance
Voltage
Resistance
Hz/frequency
Amperage
Estop
Should be cat 0 or cat 1 stop
______ controls speed
Hertz/frequency outputting from drive controls speed
of knives in wagon
Typically 2 so we don’t firetruck
Absolute encoder
Generates a numeric #, control takes # and knows what to do with it
Upper limit ~ 65,000
Incremental Encoder
Generates pulses
Transformer limitation
DC cannot go through transformer
