Energizing a relay coil ____ contacts that were normally open and ____ contacts that were normally closed
closes , opens
Making contacts
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Normally open contacts
Breaking contacts are
normally closed contacts
What happens to wire connections when you have AC Relay chatter
AC relay chatter causes contacts to crystalize and break
A better DC power supply system that eliminates the dip to zero current at anytime
3 phase full wave rectifier system
A contact on a relay that shorts out the circuit which energized the relay is called
a self holding contact
why do power companies generate AC instead of DC
it is cheaper to manufacture and it takes less wires (cables) to distribute
the secondary voltage is higher then the primary voltage. _________
step up transformer
on a hydro, can your 110v come from the controller
no, the 110v for the light and fan etc must come from a separate source
how do you plumb a hydraulic jack
use a spider bob
how do you straighten a bent hydro jack
apply heat with an acetlyne tourch on the high side
how to dress a hydro cylinder joint
dress with fine emery cloth in an up and down motion
a hydraulic leak proof joint can be made when the threads are cut _______
sharp and clean
what is the purpose of a hydro silencer or dampener (muffler)
to absorb or dampen pulsations in the oil and minimize noise going into the hoistway
why are sills grouted
to support the load
when are strainbars and boxes installed
every 100 feet down from the top of the hoistway
what is the purpose of hardware cloth
to protect the travelers during normal operation
the diameter of a traveling cable loop under the car is ________
30 times the diameter of the cable
straining wires-
it is necessary to pull up a little slack when you tie wires to a strain box
how many contacts are there in a door lock ( when a retiring cam is used)
2 sets of contacts
what are access switches used for?
running the car down from the corridor at inspection speed with the doors open
when changing leads on the line side of the main line disconnect be sure to change the leads on _______________
the load side
_________ is generally the best place to secure a positive ground
the electricians conduit
what is the purpose of grounding and bonding?
to protect the body of a person touching the equipment
a fire lintel will be necessary at floors where pass-type doors are installed . it also closes gaps between top sections
x
If an elevator door has both front and rear openings the gate contacts must be wire in?
series
rails for pass-type doors (freight) are what?
double bladed
SOS switches are located where?
either attached to the safety plank or located on the crosshead
when leveling a platform install shim between the safety plank or blocking to make the platform level
xxx
counterweight governors - should be at a trip speed greater then the car governor trip speed but not exceeding 10%
xxx
governor ropes - can be either 8 strand or 6 strand and they can be made of either traction steel or iron. these factors depend upon the design of the jaws of the governors
xxx
when one spring buffer is used for the car and one for the counterweight they should be installed so that the verticle line is within 2" of the verticle center line of the car or counterweight
xxx
What happens when the car cam strikes the final limit switch?
the power supply to the hoist motor is cut off and the car will not move in either direction
when jumping rails in a high rise installation rail alignment should overlap at least 2 full floors
xxx
a kicker shim is used when rails are out of square
xxx
the points in the building from which the elevator is located, and which serve as the basis for the entire elevator installation
axis or corridor lines
the axis or corridor lines are acquired from?
the contractors plans
rail centers, DBG, and bracket layout are gotten from where?
the final layout
a spreader bracket is a u type counterweight bracket fastened on each of the 2 counterweight rails but not fastened to the building
xxx
a channel bracket is used as a divider beam bracket. they are fastened back to back of the main guide rails in adjacent hoistways
xxx
an angle bracket is used in light duty installations and when space is at a premium
xxx
a chair or saddle bracket is used on a verticle face of concrete or brick with inserts or self drilling anchors. it can also be welded on or bolted in the web of a steel beam
xxx
the machine, machine beams, deflector sheave, and governor are located and set from the center of the rails
xxx
escalator hand rail chains should never be overtightened. it can cause pre-mature stretching and sprocket ware
xxx
the lower newel wheel - only function is to carry the hand rail. The upper newel wheel - induces the traction that drives the escalator handrail
xxx
on a modular escalator - steps can be removed anywhere in the incline
xxx
when working on a modular escalator, always engage the locking bar
xxx
the non - reversing switch on an escalator will not allow the reversal of direction without coming to a complete stop
xxx
if a hydro running platform runs up ok but has difficulty running down, you need to add dead weight to the platform
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