# Limit toqure valve



## Wirenuting (Sep 12, 2010)

kdoyle2011 said:


> If u hook up this 3 phase motor and it's going backwards will it burn up before stopping itself. Or how long will it run before burning up.


You mean this style?


----------



## kdoyle2011 (Feb 8, 2013)

Close but I mean this style.


----------



## RESI (Nov 1, 2010)

The motors in these valves run in both directions to open or close the valve in normal opeartion. Once the valve reaches the end of it's travel, either a torque switch or a limit switch stops the motor. If hooked up backwards, the valve will open when the close pushbutton is pushed and vice versa. Motor should not burn up.


----------



## Wirenuting (Sep 12, 2010)

The only time I've seen the life shortened was when the controller ordering the valve to move in a direction continues to cycle. 
This can be caused by valve drifting closed or by a faulty command open when it keeps trying to force an opened valve open.


----------



## MWayne (Nov 8, 2010)

I'm not familiar with Limitorque, but our EIM and Rotork valves need to be programmed to tell them which way is opened or closed. Even if you haven't programmed in the limit switches, over torque limits should keep the motor from burning up or destroying the valve.


----------



## Big John (May 23, 2010)

Limitorques are smart. You won't burn up anything. They're inherently overload protected and you can reverse phase rotation in your setup menu without rewiring anything.


----------



## denny3992 (Jul 12, 2010)

MWayne said:


> I'm not familiar with Limitorque, but our EIM and Rotork valves need to be programmed to tell them which way is opened or closed. Even if you haven't programmed in the limit switches, over torque limits should keep the motor from burning up or destroying the valve.


Rotork..... Blechhhhh were having lots o probs with the electronics....
Have alot of older limitorques with cam switches that are 25 + yrs old...

Like these in a valve pit...which get under water once a yr atleast


----------



## denny3992 (Jul 12, 2010)

MWayne said:


> I'm not familiar with Limitorque, but our EIM and Rotork valves need to be programmed to tell them which way is opened or closed. Even if you haven't programmed in the limit switches, over torque limits should keep the motor from burning up or destroying the valve.


Actually were looking at eims.... Any good or bad? They seem easy to replace parts if necessary, we had a demo come in to our place


----------



## MWayne (Nov 8, 2010)

denny3992 said:


> Rotork..... Blechhhhh were having lots o probs with the electronics.... Have alot of older limitorques with cam switches that are 25 + yrs old... Like these in a valve pit...which get under water once a yr atleast


People that rep many different actuators tell me that Limitorques are the best, but years ( or maybe decades ago ) the Limitorque people left us hanging on a repair. And so they are still blacklisted from bidding on our jobs! Limitorque even tried to give us an actuator as a peace offering and our management shot them down! I find the foreign made Rotorks are problematic to say the least.


----------



## MWayne (Nov 8, 2010)

denny3992 said:


> Actually were looking at eims.... Any good or bad? They seem easy to replace parts if necessary, we had a demo come in to our place


We have a bunch of Tec 2000s, since we converted them from Fieldbus they've been quite reliable. The one recurring problem is maintenance people using the hand wheel to try pinch off the last bit of flow and exceeding the amount of torque that the torque limit would allow the motor to produce and thereby ruining the over torque mechanism.


----------



## erics37 (May 7, 2009)

Did some Limitorque modulating valves at a wastewater plant last year sometime, they've been working fine. They protect themselves.


----------



## Big John (May 23, 2010)

MWayne said:


> ...The one recurring problem is maintenance people using the hand wheel to try pinch off the last bit of flow and exceeding the amount of torque that the torque limit would allow the motor to produce and thereby ruining the over torque mechanism.


 I can't swear that Limitorques don't have that problem, but I know I've seen operators reef on those valve wheels before and that was never a failure I had to repair.

When trying to move the load, the Limitorque would just reach it's maximum applied torque value immediately and display an error message. It's a mechanical problem: Clear the jam, they start operating again.


----------



## MWayne (Nov 8, 2010)

Big John said:


> I can't swear that Limitorques don't have that problem, but I know I've seen operators reef on those valve wheels before and that was never a failure I had to repair..


If that problem happens again I'll take pics of what happens with the EIMs.


----------



## MWayne (Nov 8, 2010)

Here is what I was talking about with the EIM actuators:




















On the left of this card is the absolute encoder that keeps track of actuator position, on the right is the torque arm that is attached to the main shaft and deflects like an old style torque wrench. The problem is the torque arm is plastic and tends to break where it hooks to the shaft. My apologies OP, not trying to hijack your thread.


----------



## denny3992 (Jul 12, 2010)

MWayne said:


> Here is what I was talking about with the EIM actuators:
> 
> On the left of this card is the absolute encoder that keeps track of actuator position, on the right is the torque arm that is attached to the main shaft and deflects like an old style torque wrench. The problem is the torque arm is plastic and tends to break where it hooks to the shaft. My apologies OP, not trying to hijack your thread.


No prob at all, thanks for sharing!


----------



## MWayne (Nov 8, 2010)

Here is a close up of a torque arm we replaced today, it broke because it hit the inside of the actuator from being hand cranked too hard.


----------

