Lock-out/Tag-out
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Questions
Question 1
In this motor control circuit,how would you ensure that there is no danger of electric shock prior to touching either of the motor terminals (shown as points A and B in the schematic diagram)?Describe both the action required to cure the power,and the means by which you would check for the prenc
e of hazardous voltage at the motor:
衣服广告语
Circuit On/Off Motor file 00566
Question 2
Linemen working on high-voltage conductors do not simply rely on open disconnect switches to isolate ctions of power lines from sources of electricity during maintenance.They also attach ”grounding”cables from line to line,and then to earth ground like this:
Disconnects
Disconnects
Explain why this decreas the risk of electric shock for the linemen,bad on what you know about electrically common points in a circuit.
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Question 3
Describe what the phra zero energy state means for a system,in terms of safety for tho performing maintenance work on it.
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When using a padlock to cure a disconnect device in the”open”(off)state,who should be able to open that lock?In other words,how many other people should share a key to the lock you u to cure a breaker or switch in the safe position,if you are the one working on the system?
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Question5
When curing equipment for safe maintenance,special tags are attached with the lock(s)ud to keep circuit breakers and other disconnect devices in the open(off)state.A typical”lockout”tag looks something like this:
What is the purpo of attaching such a tag to an electrical disconnect device in addition to locking it in the open position?Why is a lock,by itlf,not sufficient from a safety perspective?
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Question6
Large power distribution circuit breakers look nothing like the small breakers en in residential and commercial electrical systems.They are large units,which”plug”into cubicles so as to facilitate removal and replacement for routine maintenance.哥哥草
When curing an electrical system in a zero energy state prior to commencement of maintenance work, it is common practice to”rack out”any large circuit breakers feeding power to the system.What exactly does this term mean,and what is the procedure for”racking out”a circuit breaker?
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Question7
What step(s)must be taken after locking and tagging an electrical disconnect device for a circuit to b
e worked on,and prior to actually proceeding with the work?What step(s)come between the lock-out and the work itlf?
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Suppo you arefinishing a maintenance project where an electric motor was locked out and tagged, and now the work is complete.Your lock is the last one to be removed from the circuit breaker,everyone el already having taken their locks and tags off.What should you do before removing your lock and turning the circuit breaker back on?
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怎么压声
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Answers
Answer1
Follow the steps:
1.Open the circuit breaker.
陈漫作品2.Lock the circuit breaker in its”open”position so no one can clo it.
3.Try to start the motor by turning the On/Offswitch”on”.乐字开头的成语
4.Leave the On/Offswitch in the”off”position.
5.Test for hazardous voltage(both AC and DC)between A and B,between A and ground,and between
B and ground.
Answer2
By connecting the three wires together,you make them electrically common to each other.This prevents any substantial voltage(potential difference)developing between them.Likewi,connecting the three wires to the earth makes them electrically common to the earth,preventing any substantial voltage from developing between any of the wires and ground.
Follow-up question:after the linemen are done with their work,they remove the grounding wires from
the power lines before they clo the disconnect switches.Explain why this is done,by describing the catastrophic conquences of closing the disconnect switches with the grounding wires still in place. Answer3
杭州好玩的地方有哪些”Zero energy state”means that all sources of energy,either conducted from an outside source or stored within components of the system,have been cured so as to po no danger to the people working on the system.
Identify some sources of energy in a system that could po a safety hazard to people working on it.
Answer4
You and you alone should be able to open that lock.It needs to be a personal lock,not a lock who key is shared by other people.
Answer5
菠萝蜜的核有什么功效
A tag informs anyone wishing to turn the disconnect device”on”as to when it was turned off,and who placed the lock(s)on it.Many lockout tags have space on for a written description so that the reason for the lockout may be explained.
Answer6
To”rack out”a circuit breaker means to unplug it from its cubicle so that it cannot conduct electric power to the circuit where work is being performed,even if someone were to clo its contacts.
孩子们的英文Answer7
Check for the prence of voltage on the conductors of the circuit to be worked on.
Answer8
You should check the equipment site to be sure no one is still working on it,unaware of the impending startup.
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