In this episode, host Mike Murphy is joined by Rick Hoadley, Principle consulting Applications Engineer for ABB LV and MV Drives, to discuss active front end technology in the mining industry. Discover what safety features are available in the ACS2000.
Learn more about solutions for the mining industry.
In this episode, host Mike Murphy is joined by Rick Hoadley, Principle consulting Applications Engineer for ABB LV and MV Drives, to discuss active front end technology in the mining industry. Discover what safety features are available in the ACS2000.
Learn more about solutions for the mining industry.
Welcome to the ABB Solutions Podcast where we discuss some of the challenges faced in our industry. I'm your host, Mike Murphy speaking to you from Greenville, South Carolina. Okay, we're back with Part 2 of the ACS 2000 and Active Front End Technology in the Mining Industry. I'm going to continue my discussion with Rick Hoadley on how this technology can save space, simplify the install process, and then we'll close on some of the embedded safety features. We hope you enjoy. Okay, great. Rick, I think you mentioned something about the space needed earlier when you were describing about some of the features for active front end. But obviously space can be a commodity. So is there anything about this drive that simplifies the setup or the space needed?
Mike Hoadley:Yes, there is. And some stuff, which we did purposely, just for that. First of all, when talking about medium voltage drives, somebody would use a medium voltage drive when they have a big motor load. And they don't use that for a 25 horsepower motor, alright, it just doesn't make sense. But when you start to get to, like 1000 amps, and, and more, that's when medium voltage starts to become more cost effective in a lot of different ways. So, our medium voltage drive, the ACS 2000, can handle 300 to 3000 horsepower at 4160 volts. Now operating at 4160 volts, just by itself means the current's going to be smaller. It's about 1/8, the amount of current that you would need, if you were running on 480 volts. That means smaller wire, which means lower material costs, and also lower installation costs. So there's a big thing there with respect to installation. Usually big drives would mean big harmonics as well, right. And the issue there is, because of the active front end, we don't have big harmonics. So that's taken care of then, as opposed to six pulse or diode rectifier drive. Big drives also mean usually a big, big footprint, because with a higher voltage, you need more space between the lines, and so on. So what we did though, is because we aren't going with multi-pulse with diode bridges, we don't need a transformer. So that is a huge reduction in the footprint of the drive. The other thing is, we've really been able to make things quite compact, using these power modules, so that that they fit tightly together. And we don't really take up much footprint size. So because of that we actually have one of the smallest footprints for the power rating among our competitors. Now, there's a couple other things which we should also touch base on and one thing would be about the control. Well, the control that we have in our drive is the same type of DTC which means dynamic torque control that we use in the low voltage drives. And what this does, is this is a very high responding way to control the speed and the torque of the motor under dynamically changing conditions. So this way, we are able to maintain the speed of the motor even as loads are changing. For dramatic changes in loads, we can still very little change in the speed. So it works out very nicely for that. And it's a nice smooth control for acceleration and deceleration and so on. Here at ABB we've spent over 100 man years of design and modifying and improving our DTC type of control.
Mike Murphy:100 man years Wow. Okay. That's great.
Mike Hoadley:Yeah, it is so so that one guy is really, really old. Right, right. But what this is, it sort of calculates what that pulse pattern needs to be every 25 microseconds. So it changes things about every millisecond. So we don't have the same pattern all the time, which sometimes leads to mechanical resonances in a system. Sometimes that happens in HVAC with where you have a motor that's spinning, and it has a certain vibration frequency associated with that. And the ductwork has a natural frequency which which is in tune with that. And so you get this loud humming all the time. Well, you won't get that stuff with using our DTC. The other thing that, that is nice and simplifying the setup at all, is quality and reliability. Again, a big drive means big motors, big power, and it usually means they're on a critical process. If that goes down, usually there's nothing coming out the other end. So what we have is power semiconductors and passive components, which are all rated for the medium voltage. In fact, a lot of cases we have these IGBTs we have two in series and we can get 6600 volts minimal now with it that way. We don't require fuses on the individual phase modules like some of our competitors do. Because again, fuses do degrade over time if there's pulsating currents flowing through them, and doing the heat and things like that. But we don't need fuses on the phase modules. Now, we do have three line fuses. And that's really for overall short circuit protection. It's not for overload, but simply short circuit protection. And what it will also do, is we won't have any arc flash, then on the load side of the fuses, if they have a like a landline fault, somewhere down the line from from those fuses. Those modules, which I said, we made them nice and compact, what they are, is, we have the same module that's used for the active front end as what we use for the inverter section. I mean, it's just a set of IGBTs. And we simply tell them when to turn on and turn off. And so we made these modules exactly the same. So your spare parts, you don't have to have a spare part, which is unique for the active front end. And another one, which is unique for the inverter section. All you need is one, and it can be used in either location and any position in either location, because we have a module for phase A, B, and C on the input side, and A, B, and C on the output side. So it's really nice for the spare parts. And then, because of this modular design, it makes it easy to be able to troubleshoot, and then replace a module. Like from finding out that you need to replace a module, you can go through your your shutdown, your lockout, tagout, and then get things ready to swap things out with the phase modules. But that takes less than 30 minutes. And then you don't need any super special tools or anything. I mean, just screwdrivers and wrenches are basically it. But with that you can replace those things. And you can get back up and running in a real short period of time. We have a way we can, if you want, you can share what we call the black box inside the drive with our service guys here. And they can take a look at that black box information and determine what's going on; what might need to be replaced, and so on. And again, to be able to, in a sense, get somebody there virtually or within a few minutes as opposed to flying somebody there, which might take a day or two. That's a nice feature. Oh, that's fantastic. A lot of our customers have really enjoyed that. The way the the phase modules are connected, we use a stab, which is just like a little plate and a clip. And so these these stabs, simply slide into the clips. And so we don't have any nuts and bolts type of hardware, which you have to take care of, you just sort of just you know, pull out the phase module, the old one and slide in the new one. Because, the problem is if you're when you whenever you start taking bolts and nuts apart, there's always a possibility of dropping a nut or a washer. And then you have to spend, you know, hours trying to find it, because you're not going to turn it back on until you have that in your hand. And it's in the right location. So that really helps with respect to replacement of parts. And then we can do that, because the currents are lower. But we're not handling, you know, 1000s of amps, we're handling, you know, hundreds of amps. And so it's so much simpler for for doing things this way as compared to a low voltage drive. And then just one last thing is the capacitors that we use in our drive, all the power capacitors like on the DC bus and some of the filtering, things like that, these are foil type capacitors, they are not aluminum electrolytic capacitors, which everybody uses for the low voltage DC drives for the DC bus. What that means is that aluminum electrolytic drives if that used is that being powered up relatively frequently, then they have to be reformed. So if you have a drive, a spare drive that's sitting on a shelf, it's been sitting there for three years, suddenly you need it. Well, you really need to spend, maybe a couple of hours reforming those caps, before you put that drive into operation. Handle that and it really slows things down that way in terms of getting yourself back up and operating again. But with with these foil caps, and they're oil filled, and until the oil, if you really wanted you could cook some chicken in that oil and it wouldn't harm you if you eat it; I don't think would taste any good. So this oil is is environmentally friendly. So there's no PCBs in it. And when because it's a film cap, we don't have that reforming problem which aluminum electrolytics have, and we have a 20 year life on those capacitors. So you don't have to worry about, oh, you know, every 7 to 10 years, I'm going to have to replace the caps of my drive. And we're talking about big drives now. Which usually mean big caps. Well, that's not an issue here for for these medium voltage drives.
Mike Murphy:Okay, great. Sounds environmentally friendly, which is a great kind of segue into my last question for you, Rick. So I know very well, ABB takes safety extremely seriously on not just equipment, but personnel. So what safety features are available?
Mike Hoadley:Oh, that's great. I'm glad you asked that question. because that was another area that a lot of time went into the design and implementation of this drive to make sure that that it is safe. Let me start with this. First, we have a method which can detect a short circuit and respond to that within like 25 microseconds. That way, we can turn off the IGBTs. So that the IGBT doesn't blow up or anything else like that. Because that's, that's a problem. And maybe you've seen before where there's a fault within a drive, or maybe something externally caused that fault. And there's a catastrophic failure of the drive. Basically, you have to replace the whole drive. Well, with with this medium voltage drive, you don't want to have to go to that. Worst case, all you have to do is replace a phase module. And because we can shut things off so rapidly, we don't have phase, there's IGBT modules that would rupture and spew all this carbon and, and arcing, and stuff like that around, which just makes a mess inside of a drive, which takes another two hours to clean up. So that doesn't happen. Now, if there's a short circuit on the output side of the drive, like at the motor at the output terminals of the drive, the drive simply trips off. Nothing happens. There's no damage to the drive at all, it simply shuts off the IGBTs, it trips off and says, you know, remove that short circuit, and then we can get going again. Another thing that we do is, what about access to the drive? A lot of times on a low voltage drive, you open up the door, and you're standing there right in front of the terminals, you got 460 volts, you know, like like a foot and a half in front of you. Alright, you might have maybe a little bit of protective gear on you. But you don't want to do that with medium voltage drive. You don't stand in front of that drive, where you're exposed to the medium voltage terminals at all. If you have to get inside the drive, even if you want to put a probe on. Or if you want to check something, or you are doing your PM, anything else like that - what we do is you have to shut the drive off, lock out the upstream circuit breaker or disconnect switch what whatever might be feeding this and then use a Kirk Key system to be able to unlock the cylinders, that are on the doors, which allow access into the medium voltage sections of the drive. And so with this Kirk Key, really ensuring at another level that somebody can't simply come along and open up a door to the drive, and then then expose themselves to this, this high voltage. Now I've heard some people talk about medium voltage being like the friendly voltage, because you don't have to touch it, it'll come out and greet you, right if you get too close. So that's the whole point behind this is you don't let anybody even accidentally do something like that. They have to have that Kirk Key system to be able to to to get in there. So it's a mechanical interlock. And then there's one other thing that we do. And this I think is somewhat unique to ABB, for their medium voltage drives, is we have what's called a grounding switch on the front of the panel for the drive. Now, when the drive is, is normally operating, that grounding switch is open. But when we want to get into the drive, we have to rotate the handle of that switch to close it. Now there's a couple of things here. One is what does the ground switch actually do? One thing it does, is it shorts out the DC bus capacitors, which also in turn shorts out other capacitors that we have in our system. So it shorts, the capacitors out so there's no voltage on those capacitors. And it also grounds them. So you know that there's nothing floating. You don't have something floating at 1000 volts and just waiting for you to touch it and you get a big zap from it. So it grounds all the medium voltage circuitry and then it shorts it all out so you don't have any voltages which could be exposed to. Now when can you do that? Can you simply throw that switch when the drive is running? No. What you have to do to stop the drive. And then you have to tell it to disengage the input circuit breaker or contactor, it's usually a vacuum contactor, so it's disconnected from the medium voltage. Then you could lock that out. Then you have to wait for the voltage to come down to below 50 volts on the DC bus. Once it drops below 50 volts, then the actuator for that grounding switch is released. So now you're free to rotate it. And so now you can rotate that switch and then everything is grounded inside. Again, the thing here is you never work on the drive; you never put probes on the drive; you never go poking around inside of a medium voltage drive when power's on. You always make sure the power is off. It's locked out. You've got your Kirk Key system to keep you safe from from inadvertently going in there. You have that grounding switch, which has to be rotated in the closed position before, that also mechanically locks the door so you can open up the doors. So you have the Kirk Key and the grounding switch. And then with with all that, then you can actually go in there and you know, you're going to be safe. So actually, I feel safer when I'm working on this medium voltage drive than I do when I'm working on a low voltage drive. Because I know there's no voltage on it, and so I'll be safe. Then one last thing about about protection and all is the certifications. We have UL certification or listing for this drive. It is UL listed. So this isn't what sometimes is called self-certification. Self-certification is you've got a list of standard requirements. And you go through that list and said, yep, yep, we do that we do that we do that we do that. So I guess we're good. This is where we actually have a third party, which is UL, and they come in and, and we go to them. And we test the drive, we went through a whole bunch of different types of tests of not just the whole drive, but also various components within that drive, which they consider to be critical components. So that a person would not be harmed by some component failing inside that drive, or somebody accidentally opening up a door to that drive, anything like that. So So, all that is tested. Or if something does fail within the drive, we don't have the emission of flame and molten metal shooting through the vents or around the doors. So those are the types of tests that we went through for this. So we have the UL investigation and listing. And it's also good for CSA because it's actually called a CUL and the c part is for CSA for Canada, and UL is of course for UL here in the US. So we are listed for both CSA and UL and we meet their standards for medium voltage drives.
Mike Murphy:Alright, that's great. Plus, it's always nice to hear about a company like ABB taking those proactive steps to ensure that they're given the the safest and most quality and reliable product you know in the field. Rick, this has been great. We're gonna stop right here. But remember, if you'd like more information on the ACS 2000 active front end technology, reach out to your local sales representative. You can always go to www.abb.com. If you have any questions or possible topics about our Podcast Solutions Series, shoot us an email at us-solutions@abb.com. Thanks and have a great rest of your day.