Goody
Member
The question I would like answering is;
Is it possible for a motor that is controlled by a VFD (rather than just a contactor, to run at considerably less current while at full nameplate speed and HZ.
The story (short version)
A customer of mine was visited by a third party and an ABB expert.
They told the customer that by fitting ABB drives on about 30 of their motors considerable yearly electricity bills savings would be made. They gave actual money amounts saved.
The customer jumped at this and ordered the 30 ABB invertors.
The first ambiguity, although not really part of this is that each VFD was listed with the yearly saving figure, plus a figure of zero for fitting and commissioning.
The customer, after seeing the zero figure, thought that VFD’s were of a negligible cost to fit.
Every one of the drives are for production machinery. Mainly circulation fans for hot air from gas burners. The customer treats cloth with fire-guard and resins and the like.
Enter me. I was not privy to any of the prior discussions. All I got was ‘please fit them for us’
The first machine needed four drives fitting. These were for 4, 11KW motors. I had to make a panel and do all the interface wiring etc (The drives are quite big in physical size) The customer was upset with me because I took 3 days to do this and with parts he got a sizable bill. (he expected the fitting to be very low)
Now on to the crux of the matter.
The only way I could think of to automatically speed up and slow down these invertors was to follow the low and high fire of the gas burners.
It soon transpired that this was not working.
The correct temperature was not made in the center of the chambers. I then wired an override switch to make the invertors run at full speed (In the UK this is 50HZ) So now, most of the time the motors are running at 50HZ.
Everything is back as it was before the invertors were fitted. The customer is now not happy because he cannot see the point of the invertors in the first place.
I set up all the standard parameters on the drives including everything from the nameplate of the motors.
The customer has been in touch with the third party and ABB and they say an ABB drives expert can set up the parameters so that the motors will run at their original speed but still give the massive stated yearly savings. They say this was there intention and they were not supposed to run slower.
Does anyone know if this is so. I am attending a meeting Friday with the customer, the third party and the ABB expert. I would like to be furnished with all the relevant facts. I will either learn something I did not know or realize that the wool has been pulled over the customer’s eyes.
Please give your opinions on this.
Is it possible for a motor that is controlled by a VFD (rather than just a contactor, to run at considerably less current while at full nameplate speed and HZ.
The story (short version)
A customer of mine was visited by a third party and an ABB expert.
They told the customer that by fitting ABB drives on about 30 of their motors considerable yearly electricity bills savings would be made. They gave actual money amounts saved.
The customer jumped at this and ordered the 30 ABB invertors.
The first ambiguity, although not really part of this is that each VFD was listed with the yearly saving figure, plus a figure of zero for fitting and commissioning.
The customer, after seeing the zero figure, thought that VFD’s were of a negligible cost to fit.
Every one of the drives are for production machinery. Mainly circulation fans for hot air from gas burners. The customer treats cloth with fire-guard and resins and the like.
Enter me. I was not privy to any of the prior discussions. All I got was ‘please fit them for us’
The first machine needed four drives fitting. These were for 4, 11KW motors. I had to make a panel and do all the interface wiring etc (The drives are quite big in physical size) The customer was upset with me because I took 3 days to do this and with parts he got a sizable bill. (he expected the fitting to be very low)
Now on to the crux of the matter.
The only way I could think of to automatically speed up and slow down these invertors was to follow the low and high fire of the gas burners.
It soon transpired that this was not working.
The correct temperature was not made in the center of the chambers. I then wired an override switch to make the invertors run at full speed (In the UK this is 50HZ) So now, most of the time the motors are running at 50HZ.
Everything is back as it was before the invertors were fitted. The customer is now not happy because he cannot see the point of the invertors in the first place.
I set up all the standard parameters on the drives including everything from the nameplate of the motors.
The customer has been in touch with the third party and ABB and they say an ABB drives expert can set up the parameters so that the motors will run at their original speed but still give the massive stated yearly savings. They say this was there intention and they were not supposed to run slower.
Does anyone know if this is so. I am attending a meeting Friday with the customer, the third party and the ABB expert. I would like to be furnished with all the relevant facts. I will either learn something I did not know or realize that the wool has been pulled over the customer’s eyes.
Please give your opinions on this.