ErieTec sits down with Eaton’s UPS Manufacturer Rep. Chris Beckwith, to discuss uninterruptible power supply (UPS) and why you should have one on your equipment.
What is a ups system?
A UPS is an uninterruptible power supply. It carries the load when the utility fails until either the generator kicks in, the utility comes back on, or you can have an organized shutdown of the equipment that is being backed up. There are three basic ways of accomplishing this inside of a UPS. What are they?
1. Backup or standby UPS
A Backup or Standby UPS is a box that has an inverter, a battery, a small battery charger, and a contactor. Under normal circumstances, the utility is fed straight through the box to the load. When there’s a power outage, or if the voltage increases or decreases by a set amount, the inverter kicks on, the contactor opens up and the battery carries the load for a short period of time, typically in the range of three to five minutes. When the utility comes back on, the contactor closes, the inverter goes back off, and the battery starts recharging. This is the most simple UPS, and is only meant to provide a short backup.
2. line interactive UPS
A Line Interactive UPS provides more power quality control than a standby. Again, under normal circumstances, it will allow the utility to pass through the UPS directly to the load. It has search protection, and it has an inverter that can act as a buck or boost to the incoming utility signal. So, in addition to power outages and slight over voltages and under voltages, it can also do longer term sags and surges because the inverter can actually alter the output waveform and allow it to run while the incoming power is not perfect. Then when the utility goes out, the same thing happens with standby UPS, the contactor opens, the inverter takes the full load being supplied by the batteries and when the power comes back on, the contactor closes, the inverter backs off and the small rectifier inside will recharge the battery.
3. online or double conversion ups
An Online or Double Conversion UPS takes the incoming power and rectifies it. Between the rectifier and the next stage of the inverter, we’ve got DC power. At that point is where the batteries are connected and then the inverter creates a brand new sign wave to the output, so it can handle any kind of power quality issue, from power outages, surges, sags, over voltages, under voltages, frequency, harmonics, and transient surges. It acts as a power conditioner with a battery backup, so you get totally clean power at the output. It’s the most popular UPS. All three phase UPS that Eaton makes are true online double conversion.
Why a ups?
A UPS is used for insurance purposes. It prevents you taking a big loss when something happens with the power. As mentioned previously, especially with the double conversion, it takes all the crazy stuff out of the power, like harmonics. If you have a lot of variable speed drives in your facility, they can create a lot of harmonics that come back in and can corrupt the clean sign wave. This can affect certain equipment that’s sensitive, things like variable frequency drives, computers, PLCs, etc. Industrially, UPSs are applied in many different applications. One is for anything that uses a PLC, CNC machines of all sorts, automatic transfer switches, and VFD controls. When the power goes out, those devices can typically shut down. Anything that’s in the process on the machines are usually scrapped. The UPS will prevent that from happening.
how have ups helped?
An example where we have used UPS’s is in industrial applications. The first is a landfill in Western Pennsylvania. They use devices to collect the methane gas that is generated within the landfill, and they sell it back to natural gas companies as green gas. It is worth more in energy credits than standard natural gas, and it’s critical that the process does not go down in case of a power outage. We use the small line interactive UPS to back up every PLC in the gas side of the landfill. They have generation so they do not need long run times, they just need it to detect the outage and carry it through for approximately 30-60 seconds until the generators spin up and can carry the load again. In this example, the customer was not really worried about the power quality, they just wanted to make sure they had a backup.
The second one is a larger application. This one used a 275 kVA UPS, which is room sized. It was an orbital polisher for a mirror for a space telescope. The customer was having problems with power quality with transients from local businesses in the area starting and stopping large motors, they were also having trouble with reclosers interrupting power in the middle of the day. They asked us to provide a solution, so we came up with this UPS. It needed about 30 seconds of run time. When the power went out, they needed to lift to the arm of the polisher, allow it to come back, set it into a neutral position and just wait until the power came back on so they can resume polishing. If the orbiter were to stop in the middle of the process, or if the power just went out the entire mirror would be ruined. It would have ripples in it and they have to scrap it. It would cost hundreds of thousands of dollars. So the cost of a UPS is still way less than even one outage.
when to get a ups?
If you have a critical process where something will be damaged, like having molten metals or molten salts, for example, if the power goes out and it sets in that pipe, you have to replace all that pipe. The first thing you do should be to put a UPS on it. When the power goes out, you can get a signal saying the power is out, and you only have so much time, you can shut down the process line, allow the pipes to be evacuated, so that way nothing sets in the pipes. A lot of times, people are just used to the power going out, having their equipment fail and needing to replace it is just the cost of doing business. With a UPS you can avoid this. Why not allow things to run smoothly and not take that hit? Even if it’s relatively small, over time they add up, and can justify a UPS. This is just a small sample of what Eaton has to offer in UPS systems.
Click here for more information on what type of UPS could be right for you.
If you have an application or you think you have an application that would be right for a UPS, please reach out to your ErieTec sales representative, we would be happy to help you.
