Hi "Janitor", I have read good comments on here.
Just a brief background on who I am before I comment on your concerns of the
electric chain hoist.
I have been involved with the CM hoists since 1968 when we had to invert the gravity reversing contractor in the
hoist so it wouldn't automatically run when we used the
hoist climbing up the chain. Using the
hoist in the inverted position of the normal factory use having the
hoist stationary on a
beam clamp to an I-beam and the chain running up and down. There is nothing I do not know about a
Lodestar hoist. My company has owned a few thousand hoists in years past for sale and rental and even had our own private label
hoist called the Rigstar
Stage hoist and the Rigstar Little Rigger 1/4 ton
hoist. We also manufacturing multi
hoist control systems.
I have also been a head tour rigger for many many years on major concert and production tours throughout the world and I have seen a lot of things happen in my time.
I'm also the head rigger and
safety officer in my
stagehand local 53 IASTE as well as an
OSHA authorized outreach trainer and a CM certified
hoist technician.
Now then, I personally have been shocked by touching a chain while being up on a lighting
truss to focus lights. Not a good feeling. I have been shocked being up on the steel structure in a building rigging points. Not a good feeling.
Here's what happens when that happens, There is a hot
leg wire that is touching the
hoist casing which then will travel to the path of least resistance and that
ground when it touches the casing. Even though the
hoist may have the
ground wire from the electrical cable attached to the
hoist body the
power can still flow through other directions as well such as the chain of the
hoist and to the building steel structure and the lighting
truss itself.
It is important to never
pick up a
hoist out of the
road case by grabbing on the
electric cable of the
hoist which I have seen many stagehands do, which could cause a hot
leg in the
hoist come loose and touch the casing. Also when taking off the end covers of the
hoist and then putting the end covers back on to be careful not to pinch a
wire between the end
cover of the
hoist and the body of the
hoist. That can also cause a short.
I was up on a lighting
truss running a spot light for a U2 concert in from of the
stage and during one of the songs one of the end motors on the
truss started to run down.
At first I thought is was part of the show until I asked the LD if this
truss I was on was suppose to move, and he said NO! Good thing I was only a few feet away from the
hoist and knew what to do, so I got out of my seat and unplugged the
power cable to stop it from traveling any further. No one knew how the
hoist started to run on it's own.
But I had them turn the main
breaker off on their control
system.
Bottom
line here is about training and education of the proper use and maintenance of
electric chain hoists and control systems.
The normal 3
phase hoist that we use in our industry is usually 208-230 volts A.C.. If you
meter between any two hot legs you will get a reading of the 208-230 depending on the
power output in the building. If you
meter from any hot
leg and the casing of the
hoist you will get a reading of 110-120 volts A.C.. So when one of the hot
leg wires is touching the casing and you touch the chain or casing you will get shocked with 110-120 volts A.C.
power.
Electric hoist should no be operated while the chain of the
hoist is being rigged to the steel structure by the
high rigger. That is a normal practice during a
load in of a show.
Before any hoists are to be operated by a
stagehand they are to ask the
ground rigger if it is O.K. to run the
hoist. The steel cables that are suspending the chain of the
hoist must be completely attached to the building steel structure before operating any
hoist and that must be confirmed by the
ground rigger.
When walking away from any multi
hoist control
system the systems should always be turned off by the KILL
switch or the main
breaker on the
distro panel or remote control handle. This will cut the
power off from getting to any of the hoists.
Once the equipment that is being supported by the
electric hoists is at
trim height the main
power needs to be turned of while not needed to be used so there is no possibility of
power getting to the
hoist.
I would agree that a common standard should be implemented but you have to gather all the stagehands together to educate and train them.
It would seem simple and a no brainer for anyone off the street to run a
chain hoist. Give them a
hoist control pendent (
Pickle ) and tell them to push the
button and run the
hoist up. There is more to it than that!!!!!!
Never let a
stagehand operate running any
hoist without going over the basic operation of using the equipment first, Bottom
line!!
I can't say it enough, it's all about training, education and I don't mean just reading a
book but by hands on practice. It's not just the old saying that "Practice make Perfect" because if you are practicing the wrong ways of doing something, then it's not perfect but could be very dangerous. It's "Perfect Practice makes Perfect"
The Rigstar Training and Testing Center teaches all aspects of live entertainment rigging in a 7 days "Complete Rigger" course that is over 82 hours of class room and hands on training.
www.rigstar.com/school1.html www.rigstar.com http://www.rigstar.com/schooloutline.html
http://www.rigstar.com/Certification.html
If there is anything else that I can be of help please do not hesitate in contacting at:
[email protected] or
call 1-413-585-9869