Steve Cavill Posted October 28, 2006 Share Posted October 28, 2006 Ok, so we just purchased 4 Lodestar CM 1tonne motor hoists. The first job we used them on went well, no real problems apart from using the controller and figuring out which motor was which..but other than that it went well.. However, I over heard another guy on site, that was nothing to do with us, state that motor hoists should not be used to lift a load if the angle from the chain outlet to the item in question is greater than 5degrees. Can anyone supply me with any info on this subject, as it would be good to know before we start lifting great weights.. Also, as we have 4 of these motors, in theory, does this mean that over 4 equally spaced points we can lift a maximum of 4 tonne, strops permitting? (For those of you interested in the safety side of all this, we are using 2x 2tonne strops round the truss, 2x 2tonne strops in the roof, and 2x 8tonne safety bonds both top and bottom, so that nothing can fail...) Any info is greatly appreciated... Thanks,Steve Link to comment Share on other sites More sharing options...
AndyJones Posted October 28, 2006 Share Posted October 28, 2006 (For those of you interested in the safety side of all this, ...................., so that nothing can fail...) I'm sorry but having to ask this question, imediatly says to me that you should not be using these motors to lift at all. I would advise going on a training course or too to learn the rigging basics, or get a pro in. Link to comment Share on other sites More sharing options...
flypig Posted October 28, 2006 Share Posted October 28, 2006 My thoughts exactly Andy.IH Link to comment Share on other sites More sharing options...
Seano Posted October 28, 2006 Share Posted October 28, 2006 The first job we used them on went well, no real problems apart from using the controller and figuring out which motor was which..but other than that it went well..Perhaps labelling your cables would be worth a go. I hear that helps with figuring out which light/speaker/etc is which too. However, I over heard another guy on site, that was nothing to do with us, state that motor hoists should not be used to lift a load if the angle from the chain outlet to the item in question is greater than 5degrees.The chain should emerge from the chainport perpendicular to the motor body, yes. That doesn't mean that it has to be vertical. The motor body should not be constrained from moving, it is not a load-bearing part. When it is under tension, it should be free to align itself between the motor hook and the chain. When you work with motor chains off-vertical (what is usually described as "towing" in/out), you *must* understand the forces involved. Its very simple, but you need to understand it thoroughly. A book would be a good start, some training would be good too. I believe you've already been given a link to Total Solutions website on another thread. Chris Higgs posts here, and can be contacted via the Blue Room.Speaking of Chris, his book is one of those I'd recommend. The other one you might want to check out is Harry Donovan's book. Have a look at this thread. I'd steer clear of lifting "great weights" for a while if I were you. Also, as we have 4 of these motors, in theory, does this mean that over 4 equally spaced points we can lift a maximum of 4 tonne, strops permittingIn theory, practice is exactly the same as theory. In practice it doesn't work like that.If you lift a symmetrical square thing with a hoist on each corner, each hoist lifts 1/4 of the load IF the load is shared equally between them. If the load is fairly rigid, like a truss, one motor falling behind or running ahead will throw more weight (maybe all of it) on one diagonal pair than the other. If you have problems using a motor controller and/or figuring out which motor is which, your chances of sharing the load evenly between four motors at all times is approximately zero. (Actually its not easy at the best of times.) Also, when you start to lift something you need to apply more force than its weight to cause it to accelerate upwards. Newton's second law of motion. In the case of a model L 1 tonne lodestar, that means lifting a 1tonne weight will apply a tranient force equivalent to about 1250kg. So its not a good idea to attempt to lift more than 800kg with a 1tonne hoist. (For those of you interested in the safety side of all this, we are using 2x 2tonne strops round the truss, 2x 2tonne strops in the roof, and 2x 8tonne safety bonds both top and bottom, so that nothing can fail...)The SWL of a strop varies with how its used, depending on what exactly you do with them your 2 tonne strops could be good for 4 tonnes, or less than 1 tonne. You also need to wrap the truss correctly, as its possible to bend/break the truss if you dont. The use of safety bonds does not necessarily mean that "nothing can fail". Out of curiousity, what exactly are these "8 tonne" safety bonds? Seanx Link to comment Share on other sites More sharing options...
obsoperator Posted October 28, 2006 Share Posted October 28, 2006 Any info is greatly appreciated... You are using a precision instrument. There is danger to yourself and others if you use it without knowledge or training appropriate to the instrument. The liftwheel (the hardened steel part that moves the chain through the hoist) and the chain guides (the twin parts that guide the chain into the liftwheel are precisely machined to operate a chain that goes straight (i.e. 90 degrees) into the hoist. You are both increasing wear and risking a jam-up of a chain in motion if you don't have the load and the hoist lined up. If the chain doesn't fail today, it may fail next year, without warning - that's because hoist chain is hardened and doesn't elongate. It breaks. That's also why you shouldn't put worn-out lift chain in your car for towing. Please sign up for a chainhoist class. Link to comment Share on other sites More sharing options...
Steve Cavill Posted October 30, 2006 Author Share Posted October 30, 2006 I'm sorry but having to ask this question, imediatly says to me that you should not be using these motors to lift at all. I would advise going on a training course or too to learn the rigging basics, or get a pro in.We already have a fully qualified member of staff on our team, however, I am asking these questions here, as I do not believe that he is competent with his work methods. A rigging course has already been booked through the supplier of the motor hoists. A book would be a good start, some training would be good too. I believe you've already been given a link to Total Solutions website on another thread. Chris Higgs posts here, and can be contacted via the Blue Room.Speaking of Chris, his book is one of those I'd recommend. The other one you might want to check out is Harry Donovan's book. Have a look at this thread.A book would be a great place to start, just purchased the Chris Higgs book from Amazon, should be an interesting read, when it arrives. I, myself have done the Passport to Safety course, with a local college, so do understand the very basics of LOLER, PUWER, etc. The reasons for my questions is that the member of staff with the qualification is currently away on holiday, and we have been talking with one of the other crews that were at the event, and they have stated what I put in my previous message. I only asked so that my mind is clear so that before anything goes wrong, I can state my arguements with my fellow workmates. Thanks to those who have cleared up some of the questions, I will raise these points when I roll into work in the morning, and will probably post some more questions on this subject tomorrow night if we havent heard from the course instructors... Many thanks,Steve Link to comment Share on other sites More sharing options...
Simon Lewis Posted October 30, 2006 Share Posted October 30, 2006 [We already have a fully qualified member of staff on our team, however, I am asking these questions here, as I do not believe that he is competent with his work methods. Steve, I think your comment neatly sums up both your and our concerns....! Simon Link to comment Share on other sites More sharing options...
johnhuson Posted October 30, 2006 Share Posted October 30, 2006 We already have a fully qualified member of staff on our team, however, I am asking these questions here, as I do not believe that he is competent with his work methods. A rigging course has already been booked through the supplier of the motor hoists. Hi Steve, Would be interested to hear what qualification this member of your team has as there is currently no official qualification for entertainment rigging. There is however a much anticipated one in the pipe line, Chris Higgs and other posters from here are involved in the setting up of these qualifications. Link to comment Share on other sites More sharing options...
Tourbus Posted October 30, 2006 Share Posted October 30, 2006 I have held off commenting on this but.... However, I over heard another guy on site, that was nothing to do with us, state that motor hoists should not be used to lift a load if the angle from the chain outlet to the item in question is greater than 5degrees. Can anyone supply me with any info on this subject, as it would be good to know before we start lifting great weights.. Also, as we have 4 of these motors, in theory, does this mean that over 4 equally spaced points we can lift a maximum of 4 tonne, strops permitting? We already have a fully qualified member of staff on our team, however, I am asking these questions here, as I do not believe that he is competent with his work methods. A rigging course has already been booked through the supplier of the motor hoists. :( I personally think you are trying to dig yourself out of a hole, but are digging the wrong way! There is as far as I know no such thing as a qualified rigger. Theres an experienced rigger who hasn't done any training (such as myself), a rigger thats done training with no experience and a rigger thats done training and is expereinced. Please do give us all an example of his incompetance... I, myself have done the Passport to Safety course, with a local college, so do understand the very basics of LOLER, PUWER, etc Obviously not. If my memory serves me correctly part of LOLER is understanding loads and their relationship at angles? Link to comment Share on other sites More sharing options...
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