Variable frequency drive vacuum pumps

[Brokermike]

Does anyone have any input here? I'm new to vacuum but I have a friend up in Northern Vermont that runs a small 2hp variable frequency vacuum pump on 4,000 taps, they do very well with it and it uses much less energy than a traditional vacuum pump.

Since I'll only have about 200 taps on vacuum I'm thinking something small, quiet and efficient would be ideal. Also since I have to run 400 feet of 12-2 to reach the sugarhouse I don't want something that draws a tone of juice.

Any thoughts?

[DrTimPerkins]

Does anyone have any input here? I'm new to vacuum but I have a friend up in Northern Vermont that runs a small 2hp variable frequency vacuum pump on 4,000 taps, they do very well with it and it uses much less energy than a traditional vacuum pump.

We ran a 7.5hp oil-cooled, two-stage pump on a VFD last year in a 1,500 tap operation (yes, this is a very large pump for that # of taps, but because this is a research study, we have about 10x the amount of mainline that a standard installation would have, so lots of air to evacuate). I liked it a lot (for the most part).

Solely in terms of the VFD:

1. It'll take a fairly long time for the energy savings at 6 wks per year of use to pay back the upfront cost of the VFD and installation, but they are considerably more energy efficient as long as your system stays tight.

2. Since the VFD will throttle back the pump when you hit your vacuum setpoint, there is less heat generated, and thus less wear and tear on the pump than having it running in high speed all the time. Also less oil consumption or water cooling needed.

3. One of the primary benefits of the VFD is that the pump speed (or amperage consumption) provides a fairly decent indication of the number/size of leaks in your system. If it is running full bore, you've got big leaks (or lots of little ones), or you've got it set beyond the pump capacity to reach that vacuum level. If the pump is running nice and slow, your system is tight. Because of this, you can actually tell fairly quickly how repairs affect tubing system tightness, or if you have other problems in the woods. So it makes a good diagnostic tool in that sense.

[maplecrest]

the only thing i did not like and have not figured out how to program is if you have a slight ripple in power it shuts down and needs to be manually started. so if your boiling and have a power ripple and you do not know it your pump will be off till you go checkit. or if you have a marcoland 'sat' set up that tells you it is not running.

[WMF]

You can program most Vfd's to attempt restart a certain number of times after a power interuption.

Vfd's will wipe out AM radio reception for several hundred feet around them. May be a problem if there are houses near by.

[DrTimPerkins]

...if you have a slight ripple in power it shuts down and needs to be manually started. so if your boiling and have a power ripple and you do not know it your pump will be off till you go checkit.

We get quite a few power variations and interruptions....not just ripples, but waves, hiccups, crashes, and outages. If it's a full-fledged outage the pump will go down, but it's sailed through the other issues without any problems. I wonder if it is either the brand of VFD you're using, or if you're on the very edge of it's power limits (not enough juice).

[Amber Gold]

What are you guys using to read vac. level and controlling the speed of the pump? I have a 3 phase LR pump which is run through a VFD (converts single phase to 3 phase for the pump). I would like to get it to run variable speed if possible. Does this work if the releaser is 900' from the pump?

[DrTimPerkins]

What are you guys using to read vac. level and controlling the speed of the pump? I have a 3 phase LR pump which is run through a VFD (converts single phase to 3 phase for the pump). I would like to get it to run variable speed if possible. Does this work if the releaser is 900' from the pump?

There is a vacuum sensor (potentiometer) which is inserted into the line somewhere near the pump. It measures the vacuum level and adjusts the amperage (I believe) to the pump via the VFD. Since the sensor is placed in the vacuum line, you can put it near the pump, so the distance to the releaser is immaterial.

The signal from the sensor to the VFD, as well as the power requirements for the sensor, are fairly specific, so you'll need to find out what is suggested for your particular model of VFD. The pump motor must also be capable of being run under varying power levels.

There's a decent video explanation of the system by Lapierre at http://www.youtube.com/watch?v=JJvoj8sPFV4

[Amber Gold]

Can you list a part number(s) that will be needed to make this work?

Does the potentiometer connect directly to the VFD? The motor can be run at variable speeds.

[DrTimPerkins]

Can you list a part number(s) that will be needed to make this work?

Does the potentiometer connect directly to the VFD? The motor can be run at variable speeds.

I could tell you the part # for OUR setup, but it could very well be different from what you need depending upon your brand of VFD and the Hg sensor you use. Do you have your VFD manual? It should list the specifications for the VFD control input.

[Amber Gold]

Part #'s for your setup would be appreciated as it would give me an idea what to look for.

I do have the manual and will look at it.

[DrTimPerkins]

Part #'s for your setup would be appreciated as it would give me an idea what to look for.

Our VFD is a Cerus Industries LC-200. The associated vacuum sensor is a Setra Model 209. The specific sensor is a Setra #2091Z01PV2M1102 with a range of 0-14.7 PSIV and a 24VDC excitation. The sensor connects directly to the input on the VFD. The amperage sent to the pump is controlled by the sensor input to the VFD according to the settings you program into the VFD.

Again.....the sensor you use and the settings you use are going to be very specific to your VFD, so don't assume that this model will work with your application. Read the manual to be sure. Otherwise you could spend a good chunk of $ on a sensor that is worthless in your application.