Chain Hoist Direct Control vrs Remote Control? High Voltage vrs Low Voltage? Explanation Please

[KxSpecial]

Hello All

I often hear stories of 'you can't use that chain hoist with that control unit or it will fry it' but no-one I've ever asked for clarity can explain why.

I'm hoping to gain a better understanding of chain hoists and the differences between Direct Control (DC) and Remote Control (RC) or maybe better asked as the ability for High Voltage control or Low voltage control.
It could be that even my post title or explanation is wrong, but that's why I am here.

What I'm hoping is for a clear, educational explanation of what the differences are, the correct terminology and maybe some suggestions on what to look out for regarding the matter.

Thanks in advance

 

[egilson1]

So, a standard 3 phase hoist will have 7 wires in its fly cable. Ground, hot, hot, hot, up, down, and common. The control voltage is allowed to be up to 120v, which allows manufacturers to avoid needing a transformer to change control voltage.

In a direct control hoist there are only 4 wires. Ground, Hot, hot. Hot. Control is done externally in the controller, which allows for removing the contractor and other elements from the hoist. Saves weight.

 

[soundman]

A couple additional points -

Even if companies use the same type of motor cable and control, they may use a different pin out, PRG, Christie and SGPS all use soca 7 but they are not all wired the same.

With direct control hoists all power is removed from the motor unless the 'Go' button is pushed on the controller. This means you can't control the motor locally via a pickle.

Solotech and 5 points are the big DC companies out there but there may be smaller players in local markets.

 

[TimMc]

A couple additional points -

Even if companies use the same type of motor cable and control, they may use a different pin out, PRG, Christie and SGPS all use soca 7 but they are not all wired the same.

With direct control hoists all power is removed from the motor unless the 'Go' button is pushed on the controller. This means you can't control the motor locally via a pickle.

Solotech and 5 points are the big DC companies out there but there may be smaller players in local markets.

Solotech's direct control motors damn near made me sterile. With no local control the ground riggers have to get the hoist in the box while it's run by pendant, and my trousers, near the crotch area, were pulled into the chain guide as I wrangled the hoist into the box. Took 3 of us yelling STOP. I saved the trousers as a reason to not work with these hoists and use them as a training example.

Edit to add: this is why I feel that without pickle (local) control, these are inherently unsafe in the manner they were used.

 

[RonaldBeal]

The above posters are correct.
To expound, (and some history
Originally, CM hoists were used in industrial/factory applications, often attached to overhead trollies or swing arms.
In those applications, it was usually a single hoist, so it made sense to have power come in, and a long control lead that hung down to the ground so the operator could keep a hand on the load while running the hoist. A 15 foot pull was an average chain length. In this scenario, having all of the control bits inside the hoist makes sense for the application.

When entertainment first co-opted hoists for our use, we were using them in what was at the time, non-standard ways. Hoists were originally designed to always have the motor body up, so the early hoists used gravity relays. We would have to open up the motor and physically flip the relay pack upside down, in order to use hoists with the chain up and motor body down. (CM saw the market demand, and re-designed the systems to be spring actuated to make them more attractive to the entertainment market.)

Functionally, inside a CM hoist, the control loop sends voltage down the control common wire. When a pickle OR controller that is plugged in closes either up or down, that energizes the brake coil (to release the brake,) and the corresponding up or down contactor. (The up and down contactors are simply wired with different phase relationships to make the motor correspondingly go up or down.)

Direct control hoists have moved the control loop and contactors out of the motor body and put them in the distros. That means you only have 3 phases (plus ground) going from the distro to the hoist (instead of three phases, ground, control common, control up, control down) It makes the hoists lighter, but you need a special pickle setup in order to run the hoists locally. (usually an L21-30 with a specially wired pickle) For a large arena/stadium tour, using Stagemaker direct control hoists reduced the rig load by about 10,000 pounds... (they also use lighter chain)).

One final point... Even on remote control hoist, there is no standard wiring. So connecting 1 companies soco7 hoist to another companies soco7 distro could send hots down the control line, etc.
I have seen that happen, and it catastrophically damage equipment. (complete with pyro demonstration.)

 

[TimMc]

A bit of background on "inverted" hoists: the claim is the practice was started by Bill Hanley (sound provider for Woodstock '69, among other East coast festivals and other events), who thought it was a bad idea for riggers to be pulling hoists up to the structural steel. It's discussed in the book "Last Seat In the House", a biography of Bill and his multiple "first time" production methods.

The Last Seat in the House: The Story of Hanley Sound (American Made Music Series): Kane, John, Lopez, Ken: 9781496826817: Amazon.com: Books

The Last Seat in the House: The Story of Hanley Sound (American Made Music Series) [Kane, John, Lopez, Ken] on Amazon.com. *FREE* shipping on qualifying offers. The Last Seat in the House: The Story of Hanley Sound (American Made Music Series)

www.amazon.com

 

[avkid]

A bit of background on "inverted" hoists: the claim is the practice was started by Bill Hanley (sound provider for Woodstock '69, among other East coast festivals and other events), who thought it was a bad idea for riggers to be pulling hoists up to the structural steel. It's discussed in the book "Last Seat In the House", a biography of Bill and his multiple "first time" production methods.

http://[URL]https://www.amazon.com/dp/1496826817/?tag=controlbooth-20

[/URL]

He also built one of the first hydraulic stages!
Glad to have spent time with Bill over a few years.

 

[danTt]

Solotech's direct control motors damn near made me sterile. With no local control the ground riggers have to get the hoist in the box while it's run by pendant, and my trousers, near the crotch area, were pulled into the chain guide as I wrangled the hoist into the box. Took 3 of us yelling STOP. I saved the trousers as a reason to not work with these hoists and use them as a training example.

Edit to add: this is why I feel that without pickle (local) control, these are inherently unsafe in the manner they were used.

I've started to see shows with direct control hoists travel with run-out lines and pickles, and its definitely a big improvement. They're still much less common, mostly EU companies/shows in my experience.

 

[danTt]

Direct control hoists have moved the control loop and contactors out of the motor body and put them in the distros. That means you only have 3 phases (plus ground) going from the distro to the hoist (instead of three phases, ground, control common, control up, control down) It makes the hoists lighter, but you need a special pickle setup in order to run the hoists locally. (usually an L21-30 with a specially wired pickle) For a large arena/stadium tour, using Stagemaker direct control hoists reduced the rig load by about 10,000 pounds... (they also use lighter chain)).

The lighter chain isn't related to direct control though, is it? It's just the chain stagemaker has opted to use vs cm or liftket

 

[KxSpecial]

This is all fantastic information and I thank you all for sharing your knowledge.
The floor is still opening for anyone with anything extra to add.

 

[RonaldBeal]

The lighter chain isn't related to direct control though, is it? It's just the chain stagemaker has opted to use vs cm or liftket

Correct.

 

[derekleffew]

Edit to add: this is why I feel that without pickle (local) control, these are inherently unsafe in the manner they were used.

Agreed, fully. Unless on a dead-quiet stage with only one hoist running at a time, non-local control is inherently dangerous.

So let's talk pickles. Banana-ish shaped and sized, most often with w/ male TL, probably TL4 even though it only needs 3 conductors. Or it could be a male XLR3 or XLR4.

Or the Pocket Pickle, with everything ensconced into the shell of the male L14-20.

Handy, but not quite as ergonomic as one would like when floating motors all morning.

Are there any other alternatives?

 

[soundman]

Are there any other alternatives?

One of your fellow Las Vegas residents and grand father of modern arena rigging has been know to use a piece of 14 ga sold wire bent into a U stuck into the XLR pickle port. Later models included a bit of tie line for easier removal.

I find the factory 'banana pickles' annoying, they don't fit well in a pocket and are too bulky to carry for occasional use. I use a homemade pocket pickle.

 

[RonaldBeal]

I find the factory 'banana pickles' annoying, they don't fit well in a pocket and are too bulky to carry for occasional use. I use a homemade pocket pickle.

Which is perfect for touring.... When the local riggers can't fit the pickle in their pocket, they are less likely to accidently take them home!

I do like the 3-d printed Star Wars light saber XLR 3 pickles that a few folks are making. (sound effects not included)