Bearings practices vs. shipping damage?
Bearings practices vs. shipping damage?
(OP)
I'm involved in some tests to see if a large industrial assembly can be safely delivered by rail and/or truck. (The few motors & gearboxes have rotors in the 1000-3000 lb. range, and spherical or cyl. roller bearings. Mostly they will later end up in rather slow speed rotation (<100 rpm), although a a couple components are geared up to >1500 rpm.
Some vendor's limits on shock and vibration levels during this transit are quite low, 1 to 2 g. Well, low compared to what truck & train makers design their vehicles for.
Anyway, they don't want the bearings blocked (restrained) during transit. (Instead they seem more interested in rotating the whole drivetrain a a little bit every few minutes with an idler motor.)
Does anyone have a general rule-of-thumb about what size equipment gets bearing lock-ups or supports before transporting? (train, truck, forklift?)
Or, do you know of any industry standards or handbooks that address how fragile typical big machines are while transporting?
Some vendor's limits on shock and vibration levels during this transit are quite low, 1 to 2 g. Well, low compared to what truck & train makers design their vehicles for.
Anyway, they don't want the bearings blocked (restrained) during transit. (Instead they seem more interested in rotating the whole drivetrain a a little bit every few minutes with an idler motor.)
Does anyone have a general rule-of-thumb about what size equipment gets bearing lock-ups or supports before transporting? (train, truck, forklift?)
Or, do you know of any industry standards or handbooks that address how fragile typical big machines are while transporting?





RE: Bearings practices vs. shipping damage?
Bill
--------------------
"Why not the best?"
Jimmy Carter
RE: Bearings practices vs. shipping damage?
For what it is worth, I know that a major motor manufacturer blocks the motor shafts on all 440 Frame and above motors and on 2 Pole motors 400 frame and above. (The frame sizes are NEMA).
Thanks
RE: Bearings practices vs. shipping damage?
Typically, what I see is shafts restrained from turning freely, for instance in the case of 5000+ HP motors which is usually done by an endplate which bolts to the housing. They don't seem to concerned about the shaft 'bouncing' on the bearings being an issue.
Its similar for both small and large machining centers, typically they'll have the head blocked out and/or restrained with strapping to prevent it from sliding sideways or moving up and down in the event that something gives, but again, nothing is isolated from the bearings to stop any shock loads.
Depending on what the assembly actually is there's a good chance I've moved one and I can give you some more specific information as to what was done to it if you'd kindly mention what this assembly is/does. That is to say, if you tell me its a VTC, HTC, mill, casting machine, whatever, I can (usually) tell you how we'd block it out for transport.
RE: Bearings practices vs. shipping damage?
EPRI has several publications which specify shaft blocking for shipping of any motor big enough to be rewound/refurbished. (in other words, both their form-wound and random wound motor rewind/refurbishment spec specifies blocking).
=====================================
Eng-tips forums: The best place on the web for engineering discussions.
RE: Bearings practices vs. shipping damage?
RE: Bearings practices vs. shipping damage?
=====================================
Eng-tips forums: The best place on the web for engineering discussions.
RE: Bearings practices vs. shipping damage?
=====================================
Eng-tips forums: The best place on the web for engineering discussions.
RE: Bearings practices vs. shipping damage?
Chris
"In this house, we obey the laws of thermodynamics." Homer Simpson