Is there a reliable, low cost, cont

[Palibacsi]

Is there a reliable, low cost, controlled holding torque electric drive system that will hold a positioning indexer against fixed index stop, without heat-up, and cooking of the drive?
It must maintain torque against the stop, and start movement requiring high torque as the stop escapement is released.
The duration of stop is randomly variable, from a few seconds, to up to days..(This is why heat generation in the electric drive is not acceptable.)
I am using a pneumatic drive in this application, that is always "ON". However would like to improve starting reliability by going all electric.

 

[peterpom]

Hi there,

Why do you not consider a hydraulic system for this? Any electrical system will heat up whilst being held in a stalled condition. The only other option, is to install sufficient cooling capacity to keep the electrical actuator temperature under control.

It seems to me that the problem with the pneumatic system is 'stickion' where the seals of the actuator partially stick to the body of the actuator, and cause uncertain start-up. This can be beaten by changing the elastomer of the seals, to PTFE or HMWPE or one of the low friction compounds. To this add increased operating pressure, and the problem will probably fade away.

I hope this helps,

Peter.

 

[nbucska]

Szervusz palibacsi !
kuldj specifikaciot E-maillel. <nbucska@pcperipherals.com>

 

[TheDOG]

How much holding torque is required?

 

[designerman]

Yes, there are ways to build a torque device that will not HEAT UP..or at least will stay cool enough to last a life time. You do not indicate the type of continious drive you are using, and thus how much energy is going into the system. This,of course must be dissipated as heat energy discharged. Are you having a turntable for HUGE or MICRO loads? What are the FORCES that are generated to dislodge the work from the stop?. If you want HELP, we need to know much more, than just HELP !!!! Look up SLIP CLUTCHES, they come in many forms, spring detents, magnetic drag, viscious drag, friction discs.. to name a few. Sounds like you need SYSTEMS ENGINEERING so you don't have to fight the servo. Try an make one unit do one thing. MOVE and HOLD are 2 things. Move should MOVE, Hold should LOCK the unit.
..need more help.. let me know.

Dick Bowman
designky@apex.net

http://www.inc.com/users/designky.html

Practical solutions, innovative designs, have 30 + projects left-over problem solving, age 71, been there done that, too many projects too good to stay dusty. Active, real, ready to share on WIN WIN WIN basis. References

 

[parima]

hi designerman, Doug,

would you like to comment on my thread, &quot;Looking for Hydraulic?hydrostatic assist&quot;

I want to build a large force driver (hydrostatic motor) that can be controlled
by a rf servo (model airplane type)
for acurately moving and positioning heavy loads.

thanks,
paul.