witch the better of energy saving VFD or VSD HYDRODYNAMIC

[faycalleroi]

hello
in pumping sation of oil we use a hydrodynamic fluid coupleur to change flow for pump and the driver is a HV motor (2.5 MW).so we would change the hydrodynamic coupleur by a HV variable fraquency driver. is it a good idea?and for annual energy cost witch the better?
best regards

 

[Skogsgurra]

Typical losses for an MV VFD plus motor is better than 90% from grid to motor shaft.
I have yet to see a hydraulic drive that beats that.

Think about it, you first need an electric motor to run the hydraulic pump. Then, there are the losses in the pump, losses in the hydraulic motor (and possibly in the tubing between pump and motor - if there's a distance). These losses add up to at least 20%. Probably more. We do not know what equipment you have, so it is difficult to make an exact guess. But you will typically lose at least twice the energy in a hydraulic drive vs a VFD.

Then, there's the maintenance and reliability part of the story. Hydraulic drives do well in very rough environments. VFDs do better in more "civilized" environments.

Gunnar Englund

http://www.gke.org

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Half full - Half empty? I don't mind. It's what in it that counts.

 

[faycalleroi]

I MUST inform u that our hydraodynamic drive use the same motor and pump so there is not a more change and the effeciency may be still the same or better than a hv vfd ( our hydrodynamic fluid drive is vorecon from voith)
regards

 

[cswilson]

skogs - I think you meant that efficiency is better than 90%, not losses.

You must have been listening to Obama when he said that he wanted to "increase the inefficiencies in our health care system"...

 

[Skogsgurra]

Of course, Curt. Efficiency is better than 90% serious slip of mind.

Et à vous, faycalleroi, il faut dire que la pompe n'est pas la pompe même, mais la pompe dans l'convertisseur hydraulique. Sans la convertisseur vous évitez les pertes de la même. Les pertes d'invertisseur sont beaucoup plus faibles que les pertes du convertisseur.

Why French? Because I think that faycalleroi speaks better French than English. "coupleur" and a few other characteristics are give-aways.



Gunnar Englund

http://www.gke.org

--------------------------------------
Half full - Half empty? I don't mind. It's what in it that counts.

 

[itsmoked]

Ah.. Skogs our forensic language leader.

Keith Cress
kcress -

http://www.flaminsystems.com

 

[DRWeig]

Skogs (or one of you who knows), for my education -- the pump operating the hydrodynamic speed changer is on the same shaft as the pump motor? So there's just one motor, but two pumps?

Best to you,

Goober Dave

Haven't see the forum policies? Do so now: Forum Policies

 

[waross]

Take a look at this link Dave. Page 4.

http://www.kanitengineering.com/pdf...f?phpMyAdmin=cecc8373409f3f7facdfa4dce0732523

Bill
--------------------
"Why not the best?"
Jimmy Carter

 

[Skogsgurra]

I had another hydraulic drive in mind. The Vorecon combines hydraulic pump and motor into one unit, the torque converter. That makes my reasoning less valid. Looking at the efficiency curve, one can see that efficiency goes from 80% at 30% speed to 95% at 80% speed.

That is not bad. But if operation is across the whole speed range, a VFD is better.

I have done measurements on hydraulic drives for huge iron ore rotating kilns. There, efficiency was much worse than on page 3 in Bill's link. They were Hagglunds drives and had been chosen because of the high torque available at zero speed. I am afraid the Vorecon couldn't be used in such an application because efficiency drops to near zero (100% losses) at zero speed. I imagine that the oil would boil if one tried to start a loaded kiln with all the iron ore at the bottom. Start takes a very long time.

The efficiency of the Vorecon depends a lot on at what speed it is running. If running contibuously at around 80% rated speed, it seems to be a good choice. At lower speeds, it is not. But if it is about pumping oil, there are probably Atex restrictions and then, the hydraulic drive may be the only practical drive to use.



Gunnar Englund

http://www.gke.org

--------------------------------------
Half full - Half empty? I don't mind. It's what in it that counts.

 

[DRWeig]

Thank you Bill!

Best to you,

Goober Dave

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