vfd question

[petersonra]

The power electronics are the same as the high end, just the software, control end and interface changes. The motors on these applications fail more often than any other drive applications.

I would not be at all surprised. HVAC equipment tends to use the cheapest of everything.

 

[weressl]

I would not be at all surprised. HVAC equipment tends to use the cheapest of everything.

But the drive isn't failing, it is the motor and it is due to lack of application engineering. It has nothing to do with cheapness.

 

[steveng]

ABB USE201421-ZZ$2,939.00 each

You would want to have 4 pressure transmitters with 4-20mA signal and you can utilize the built-in P&ID controller for pressure control. The main issue is that if any of these are operating on a common air duct system you are never able to control them properly, regardless what sophisticated algorithm you are trying to use. You can tune out the frequencies around the resonant RPM's. Make sure that the motors are rated for inverter service; otherwise you should schedule the replacement of those too.

i appreciate the opinions expressed here, you guys are a wealth of knowlwdge and info,

my concern is getting my money's worth and saving myself from future work,
these motors are marathon and have lasted almost 30 yrs , im sure they are not inverter rated, however, the previous 7 abb drives all failed before the
motors.

the hvac equipment was installed in 77 and the drives we installed in 90 during an energy grant, and lasted approx 7 yrs, i dont have the model number with me, but one of them is still on the wall.

the original equipment hvac was designed at 1.5" - 2.0"static, it is a vav design, 60hz axial forward curved blower. with across the line start.

based on the design we are utilizing, i will try to run these at 50hz or less depending on my hvac load, we have run them previously at this speed in a manual mode. the duct design is a 2 story bldg, the return air is thru the ceiling

thanks again
Steve

 

[weressl]

i appreciate the opinions expressed here, you guys are a wealth of knowlwdge and info,

my concern is getting my money's worth and saving myself from future work,
these motors are marathon and have lasted almost 30 yrs , im sure they are not inverter rated, however, the previous 7 abb drives all failed before the
motors.

the hvac equipment was installed in 77 and the drives we installed in 90 during an energy grant, and lasted approx 7 yrs, i dont have the model number with me, but one of them is still on the wall.

the original equipment hvac was designed at 1.5" - 2.0"static, it is a vav design, 60hz axial forward curved blower. with across the line start.

based on the design we are utilizing, i will try to run these at 50hz or less depending on my hvac load, we have run them previously at this speed in a manual mode. the duct design is a 2 story bldg, the return air is thru the ceiling

thanks again
Steve

Do you have an isolation contactor either on the input or output side of the drive? If you open those while the drive is running could cause premature failure of the drive.

Capacitors could fail within 7 years. Newer capcitors are designed for 10 years. I have some drives in service with the original caps since '74. Its a crapshoot.

 

[chaterpilar]

What i have used till now are ABB, Square D, Danfoss, and Mitsubishi drives..

They are all at par in reliabiity.....what really makes the difference is the "3 am call".....how good is the after sales service....

I check the after sales service from the clients of the supplier before deciding the brand.

You have the smartest VSD of the world but if it is not backed up by support...then it really does not count...

Cheers.

 

[ptonsparky]

Recently bought a Altivar 31 (SQ D) to use on a water pump. My one support call was handled very well and I did not feel like a complete idiot while talking to them or after I hung up. That alone will keep me buying their product.

This drive was on the low end for price and options. Does everthing needed.

 

[steveng]

recently, one of the new square d drives went down on a short circuit, ground fault, i attempted to run the fan in bypass and the high static limit shut me down, so now, im waiting for the warranty service to show, one good thing about this hvac design is the unit that went down was an oahu,
so the ahus common to this one just sped up their drives to take up the slack, i was able to manually open to chw valve to precool the make up air
drawn thru the dead unit.

engineering design, worked! yeah!!!:grin:

thanks\
steve

 

[Jraef]

Recently bought a Altivar 31 (SQ D) to use on a water pump. My one support call was handled very well and I did not feel like a complete idiot while talking to them or after I hung up. That alone will keep me buying their product.

This drive was on the low end for price and options. Does everthing needed.

I, on the other hand, had trouble setting up and stabilizing a simple PID loop on an Square D Altivar 71 drive and used up 600 minutes of my cell phone time with their <useless> tech support people before deciding it would be cheaper to jettison that drive and put in a different brand (I have set up hundreds of PID loops with other brands of drives and stand-alone controllers; I know what I am doing). I was able to set up the PID loop in the replacement drive in 10 minutes.

I also once had a customer who bought a VFD from Automation Direct and had trouble with it. I came out to troubleshoot it and called their toll free tech support line. I was put on hold and nobody picked up. After a while I decided to see how long they would let me wait, so I stayed on (speaker phone in the room) for 2 hours, nobody ever picked up. I eventually diagnosed the problem myself (blown capacitor) but I saw the value of their "free" tech support.

So I agree with the other comment that the hardware is somewhat meaningless, it's the support that counts. Ask around in YOUR AREA who provides good support of their products, regardless of brand. That, in the long run, will mean a lot more to you.

 

[steveng]

I, on the other hand, had trouble setting up and stabilizing a simple PID loop on an Square D Altivar 71 drive and used up 600 minutes of my cell phone time with their <useless> tech support people before deciding it would be cheaper to jettison that drive and put in a different brand (I have set up hundreds of PID loops with other brands of drives and stand-alone controllers; I know what I am doing). I was able to set up the PID loop in the replacement drive in 10 minutes.

I also once had a customer who bought a VFD from Automation Direct and had trouble with it. I came out to troubleshoot it and called their toll free tech support line. I was put on hold and nobody picked up. After a while I decided to see how long they would let me wait, so I stayed on (speaker phone in the room) for 2 hours, nobody ever picked up. I eventually diagnosed the problem myself (blown capacitor) but I saw the value of their "free" tech support.

So I agree with the other comment that the hardware is somewhat meaningless, it's the support that counts. Ask around in YOUR AREA who provides good support of their products, regardless of brand. That, in the long run, will mean a lot more to you.

thanks jraef, i agreee, ..

 

[petersonra]

40HP is a small drive to you?

These days I would say it is close to a small drive.

The latest example was a high end drive added to a 15HP motor by one of the technicians. It was a fan application. The bearings got chewed up in short order, the race was like a moto-cross run and the balls had small craters in them. The motor WAS inverter rated. No winding damage.

Bearing current problems are pretty rare. you can have hundreds or even thousands of VFDs installed in a plant and never run across one.

I don't know how true it is, but I have read that there is a significant correlation of use of higher VFD carrier frequencies to bearing damage.