What's new
What's new

Abb ach series (hvac) drive suitable for lathe motor?

skippy

Aluminum
Joined
Feb 17, 2005
Location
Canberra Australia
Guys,

I'm looking at purchasing a variable frequency drive for my metal lathe. I'm currently looking at a cheap ABB 5.5kw drive on fleabay, but it is listed as the ACH series, suitable for HVAC applications, not the ACS industrial series. I've downloaded the manual for the ACH series and had a read. It's apparently suitable for fans, pumps, and condensers. While the drive can be configured with the For/Rev Start/Stop input and the 0-10 vdc controls I want, I don't know if this drive will be unsuitable for a lathe motor with the associated varying loads.

I would be thankful of any advice you may have.

Cheers, Steve
 
I do not know that specific unit.

That said, the HVAC units are usually cut-back versions of regular units. HVAC is all about first cost, so if you can be a few pennies cheaper, you get the order.

Often the difference is largely in the programming, with advanced features such as vector control and PM motor control left out. Sensors may be left out where possible if not needed for basic operation, display may be less fancy (or even left out), etc. They WILL have building automation interfaces, generally, but that doesn't get in the way, it's generally a serial link that isn't required to operate.

The biggest problem would be if there is a non-defeatable low speed "boost" programmed-in. That fouls up the volts/Hz curve at the low end somewhat. may not be an issue depending on usage.

Generally, all of them will work with a speed pot, HVAC or not.
 
The output current rating will be lower because it is intended for "variable torque" loads where the torque/current requirements drop with speed. On a machine tool, the torque requirement is usually constant. So you will need to de-rate the drive to be equivalent.

Also as a general rule, you may not get "Vector Control" as an option, which means likely instability at low speeds, which is what JST is talking about. That may or may not be an issue, only you will know what you want out of your lathe.
 
The output current rating will be lower because it is intended for "variable torque" loads where the torque/current requirements drop with speed. On a machine tool, the torque requirement is usually constant. So you will need to de-rate the drive to be equivalent.

Also as a general rule, you may not get "Vector Control" as an option, which means likely instability at low speeds, which is what JST is talking about. That may or may not be an issue, only you will know what you want out of your lathe.

They will all operate OK as V/Hz drives.

Good brands will NOT need derating, go by the real current rating. Should be in teh specs.

They can be a good value for basic VFD. Not for advanced features, etc, which they will not as a rule have,.
 
Read up on the information and features of the full featured industrial unit. See where the specs and capabilities diverge. Make some evaluation regarding your acceptance of the trade offs.

I'm always amazed at what these electro-magic devices can do!
 
Thanks guys,

The drive has a nominal rating of 5.5kw and 11.9 amps. The Baldor 5hp motor has a nominal amps of 8.7 amps at 415 volts. The manual for the drive makes reference to a 'sensor-less vector control mode', so it is starting to look quite attractive. (Especially for $100.)

I must say, ABB sure know how to write a manual compared to some of the no-name Chinese imports - 474 pages of detailed information. I'll spend a few hours this weekend trawling through it, but it looks like 95% of what the drive does, I won't require.

Cheers,

Steve
 
Thanks guys,

The drive has a nominal rating of 5.5kw and 11.9 amps. The Baldor 5hp motor has a nominal amps of 8.7 amps at 415 volts. The manual for the drive makes reference to a 'sensor-less vector control mode', so it is starting to look quite attractive. (Especially for $100.)

I must say, ABB sure know how to write a manual compared to some of the no-name Chinese imports - 474 pages of detailed information. I'll spend a few hours this weekend trawling through it, but it looks like 95% of what the drive does, I won't require.

Cheers,

Steve
The difference in VT ratings (HVAC drives) and CT ratings (machine tool drives) is not in the rated AMPS of the drive, it is in the OVERLOAD capacity. A CT rating assumes you want maximum torque capability (Break Down Torque, roughly 200% of FLT) from the motor at any speed and to deliver that, the VFD must deliver 200% current. So a typical CT rated drive will have an overload capacity of 150% for 60 seconds, >200% for 3 seconds.

A VT /HVAC drive is NEVER expected to deliver that much current, because you cannot make a variable torque load such as a centrifugal pump or fan pull that much current unless there is a problem, in which case you want to shut it down anyway. So a VT drive is rated at 110% overload for 60 seconds, maybe 150% for 2 or 3 seconds. If you want BDT from the motor, the VFD will never allow it.

That was all achedemic however, because in this case, the motor is smaller than the drive (you left out the motor size before), so that is usually the only real difference anyway. You may only be able to program the maximum current limit to a lower percentage, but that is a lower percentage of a higher number, so it will be fine.
 
Got the drive today and ran it with the motor with no load. (It will be about a year till the lathe is finished and ready to take a cut.) Used the default settings, tweaked a bit for faster acceleration on start up. I've also played with the Switching Frequency, using 12kHz to quieten the motor down a bit. It seems to run better as 'Scalar' than it does as 'Vector' I probably need to fiddle with it a bit more.

Guess I won't know what it is really like until I get it under a good load, but so far, so good - thanks for the advice.

Cheers,

Steve
 
Scalar will appear better with no load on it, SVC is seeing the lack of load and doesn't know what to do about it, because SVC use would PRESUME that you want to actually load the motor. So don't judge the performance based on what you see with no load, that means nothing. SVC will require you to go through the "autotune" procedure though.

The higher the switching frequency, the higher the switching loses in the VFD (which likely don't matter here because it is over sized anyway) and the higher the likelihood of creating motor bearing problems. You want the switching frequency to be as low as you can bear it, it's better for the motor and the drive. Again, don't judge by what you hear now, once you have it connected to the machine and under load, that noise may be completely lost in the other noises.

Just as a point of fact though, raising the switching frequency does not technically reduce the noise, it just moves it above the range of human hearing. It's still just as noisy, ask your dog...
 
Guys,

Well, life got in the way of the lathe project, and it took me over three years to get to the point where I could fit the motor and drive the spindle. In the meantime, I continued reading threads on VFDs, scalar/vector control, etc. While I can't claim to have understood everything, I appreciate the detailed explanations provided by guys such as Jraef and Motion Guru.

Anyway, I've set the drive to 'HVAC default', and the motor control mode to 'Vector:Speed', and left everything else alone. I'm fairly happy with the operation, the only gripe I have is that when you start a cut, the speed will drop a few percent for a second, before the drive picks up the slack. While I understand that this may be due to the drive being ACH series, not a an ACS series, would anyone like to suggest any parameters that could be changed to improve the response/performance of the drive?

Cheers, Steve
 
The reason is is likely doing that is related to it being ACH instead of ACS. As I mentioned, the VT rating will mean the drive is incapable of handling an overload condition, in this case as brought on by increasing the load. So the drive will protect itself by going into "current limit", which in order for that to function, results in it overriding your commanded speed and slowing down to shed loading. If you didn't over size the drive, the Current Limit will max out at 105-110% of the drive rating, as opposed to 150% for the ACS sized as Constant Torque of the same HP rating. Not much you can do about it now though.
 
Guys,

Well, life got in the way of the lathe project, and it took me over three years to get to the point where I could fit the motor and drive the spindle. In the meantime, I continued reading threads on VFDs, scalar/vector control, etc. While I can't claim to have understood everything, I appreciate the detailed explanations provided by guys such as Jraef and Motion Guru.

Anyway, I've set the drive to 'HVAC default', and the motor control mode to 'Vector:Speed', and left everything else alone. I'm fairly happy with the operation, the only gripe I have is that when you start a cut, the speed will drop a few percent for a second, before the drive picks up the slack. While I understand that this may be due to the drive being ACH series, not a an ACS series, would anyone like to suggest any parameters that could be changed to improve the response/performance of the drive?

Cheers, Steve

Take a look PID parameters and/or autotuning starting around pg 231 (my crystall ball tells you have ACH550 drive?)
https://library.e.abb.com/public/debb3e43999f4e55c1257d0b00267491/EN_ACH550_01_UM_G_A4.pdf

parameter 2605 is another important for lower than nominal speed operation, you'll want linear u/f ratio because this is not a pump..
aaand 2608 sets slip compensation, you can start with 100% and increase it in 10% steps to see if it improves things.

Also check max torque setting, this can be set 0 to 600% motor nominal. Start with 200%
(201x parameter group)

To me the ACH series looks like it has specific modes to HVAC and pump applications and specific I/O buses to hvac automation, not so much that it would be any cheaper construction.
 
Thanks Mattij,

I've just come up from the workshop after doing what you suggested.

I changed the Volt/Frequency ratio from 'squared' to 'Linear' The manual notes that: "Linear is preferred for constant torque applications."

I also changed the Slip Compensation ratio from 0 to 100%, A separate ABB document notes that: "Slip compensation is a feature that improves speed regulation by increasing the drive output frequency slightly in proportion to an increase in motor load. The slight frequency increase compensates for the speed decrease that would otherwise occur as the motor’s slip increases due to the increased load."

When under load, there is hardly a flicker in the RPM. (Note that I had to change the Motor Control Mode back from 'Vector' to the default 'Scalar', so that Slip Compensation could be changed.)

Now, I don't know if here are any downsides to what I've just done!!!

Thanks again, Steve


PS. I'm staying well away from PID stuff - it always ends in tears.
 
Last edited:
PS. I'm staying well away from PID stuff - it always ends in tears.
:D

You lose on low rpm torque by not using vector control but if the speed range is sufficient even with scalar mode you are golden.

I have ABB drive with crane/hoist software on my bench drill... it also has it's peculiarities like possibility to start with full torque against brake :D
and torque control hmmmm... tapping to blind holes with torque limit? :nutter:
Some of the basic functions are missing in that software but luckily nothing fatal in my case.
 
Hello. I have a Ab ACH550-uh-06a1-6 HVAC vfd I am currently trying to hook up tp a milling machine. I have the motor able to start and stop with a remote
switch ,but cannot get the potentiometer to work. I have it wired according to the manual but no response. Any suggestions ?
Rick.
 
I only have a minimal amount of experience with these drives, but could I suggest an incompatible parameter setting, or an incorrect physical jumper on the digital inputs? Assuming that the drive you have is second hand, did you remove all of the existing jumpers, and restored the default factory settings by macro HVAC settings? Other than that, I can only suggest a deep dive into the mind-bogglingly detailed manual.
Hopefully, someone with heaps more experience will chip in with the correct answer later today. Cheers, Skippy.
 
Probably settings/parameter related. They can be a little confusing. I've got a couple Hitachi drives that are similar, parameters about other parameters. Very complicated, but a lot of possibilities. A little trial and error helps sometimes.
 
In all VFDs, you must program the VFD to tell it two main things:
1) Where is the Comman /control going to come from? For example the keypad, a communications port or the digital I/O terminals.
2) Where is the speed reference going to come from? For example the keypad, a communications port or the analog input.

They are separate issues, you must at the very least program them both.

In some brands of VFDs, you can select whether you want the drive to run as Constant Torque or Variable Torque, which is all about the overload capability of the drive. Unfortunately in the ABB ACH series, the “H” means HVAC applications like centrifugal fans and pumps, so to prevent it from competing with their ACS series, it is purposely NOT able to be reprogrammed for Constant Torque operation. So that makes it generally unsuitable for using on machine tools.
 








 
Back
Top