32 replies to this topic

[Arthur]

https://www.google.c...mAuqmJRifORpXk=

 

 

TEFC motor the fan in the end cap blows air over the finned body to cool it. There is NO way in for dust.  Lots of sizes exist.

[MadMat]

Actually I was thinking of the toro method when I said that. Opps, I never thought about the possibility of dusting dry comp on the growing stars. But then again, I have never rolled stars (yet). Hmm... I once saw a video of someone that used an electric drill to power his star roller. You know the kind of drill that has vents right over where the brushes are.... I guess it's just another reminder NOT to pay to much attention to You tube videos.

Edited by MadMat, 28 May 2016 - 02:42 PM.

[Arthur]

It's you that will get burned in a fire, it's you who must think how to minimise the risk and degree of burns. Youtube is for entertainment not for learning -unless you know and trust the author.

[lloyd]

Arthur,

Being in the business of making automated machinery to build explosive devices, I've had to spend a bit of time around hazardous location motors.

 

I know you didn't intend to muddy the issue, but I need to make clear to others here with less experience that JUST being a TEFC or TENV motor does not, in and of itself, ensure that it's designed for a hazardous location.

 

Often, such motors are built specifically to protect themselves against abrasion hazards, but without specific thought being given to ignition, containment, and combustion gasses cooling.

 

For a motor to be "properly safe" in an explosive environment, it must be a Class II (dusts) or Class I (gasses) or combined Class I & II hazardous location motor.

 

Class II motors exclude dusts using seals on their shafts.  Class I motors contain and cool combustion gasses before allowing the cooled products to exit around the shafts.

 

Most pyrotechnic applications (except where flammable solvents are used) will require a Class II motor at a minimum, although a combined-Class I/II is better protection, and will allow the use of flammable solvents, also.  Class III motors are NOT suitable for use in explosive environments.

 

Most amateurs opt NOT to pay the rather steep premium for class-approved hazardous location motors, unless they're lucky enough to find used ones inexpensively.  That's why we like to dwell on the other ways they can be kept safer.

 

Here's a decent SHORT writeup on the classes and divisions for haz-loc motors:  http://ecmweb.com/co...rdous-locations

 

LLoyd

Edited by lloyd, 28 May 2016 - 03:35 PM.

[memo]

i have a tefc coming for this

 

 

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[MadMat]

O.K. I don't know much about rolling stars, but are the vanes in a cement mixer a problem?

[memo]

ha , they are coming out , in fact they are out right now. i just got it this morning

[lloyd]

Mad,

"Problem"?  For rolling stars, yes?  To get out of there?  No, not usually.

 

They need to come out, and their bolt holes should be smoothly filled such that they don't bounce and damage stars any more than necessary.

 

Some folks have puttied the holes shut, while others have used flattened carriage bolts to present the barest minimum of 'head' showing inside the drum.

 

Lloyd

[memo]

i have a mig welder, just going to weld them and sand them, little body puddy and its good to go

Edited by memo, 28 May 2016 - 04:23 PM.

[lloyd]

Yep... MIG or TIG would be just the trick... but with some careful jigging, you could probably even braze them shut with an O/A rig.

 

Lloyd

[calebkessinger]

Mine are just welded up and ground off.  Way more better.    

[Arthur]

Here is a machine using a through the wall drive shaft. 

 

 

I'm well aware that hazardous area motors are rare on the consumer market and expensive, that's why I mentioned that TEFC is better than an open frame motor. I've also seen, in a UK factory, the use of hydraulics through the wall to keep sparks away from machines.

 

As amateurs keeping the price down and the safety up is the usual problem.

[lloyd]

Arthur,

Most of my machines get their motive force from pneumatics or hydraulics.  The only electricals are associated with the controlling devices and valves, which are suitably housed in Class I/II pressurized enclosures.

 

LLoyd