It’s really kind of shocking how quickly those motors will stop.
Show us your VFD conversions/installations
- Thread starter Techie1961
- Start date
It’s really kind of shocking how quickly those motors will stop.
My shop smith mill controller.
I like the look. What is the drill press?
What motor did you end up using?
a6hux
Well-known member
1940's Shop Smith, Ohio Electric Company 220v DC motor, Penta Drive Controller.
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cosmopedro
Well-known member
New to VFD's so bear with me... so, if I have a 3PH 5HP 200V compressor motor and I'm looking to run it on single phase power, do I need to get a greater than 5HP drive? And how do I know if I'm getting a decent one, or one that was made in some third-world backyard that won't do what I need or do it for long?
And, lastly, would it make more sense to just buy a compressor-rated 5HP single phase motor from somewhere like Surplus Center?
thanks!
Invertek has a 5HP single phase input drive that's nema 4x/IP66 rated with local controls (all you'd need would be to hook up the pressure switch), runs about $1k. a motor would probably be cheaper, unless it's a really nice motor.
cosmopedro
Well-known member
Thanks, but I can source a motor for about a third of that cost, so...
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jsharp4684
New member
- Joined
- Jun 9, 2015
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Thought you all might appreciate this pic. These are trolley bus brake resistors. When they're regenerative braking, they'll put current back in their battery pack. If that's full, then they'll push back to the grid. If they can't do that for some reason, then they'll push to the brake resistor. The really old buses would use it as part of the HVAC system.
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Strouty
Well-known member
If I want to power a 10hp rotary screw compressor (3 phase), can it be done economically with a VFD or am I living a pipe dream?
slodat
ALLIANCE MEMBER
What's the continuous current of the compressor?
Strouty
Well-known member
I didn't look at the motor itself (stupidly), but the tag for the compressor says 30 amp contactor, also says "locked rotor amp rating of assembly" 450, so if it was to start loaded, she would draw a **** load.
As a single phase example, my current compressor has a 10 HP motor and the inrush is 237 amps, but it only draws something like 40 after that under normal load.
As a single phase example, my current compressor has a 10 HP motor and the inrush is 237 amps, but it only draws something like 40 after that under normal load.
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seems like yes it's doable, if your version of "economical" includes buying an expensive VFD.
Depending on the manufacturer, you need to upsize the drive you buy to single phase input a 3 phase drive (the drives i've been buying say 100% oversize, so 20hp drive to run a 10hp motor on single phase input), then disable the phase loss protection and a few other small tweaks.
a hitachi 30hp P1-01240-LFUF is under $2k, not bad in my book. replacement for the SJ-700 series.
FYI i have a couple invertek drives. I got the IP66/nema 4x rated ones and I am quite happy with them.
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slodat
ALLIANCE MEMBER
Like I said the new(er) Hitachi SJ-P1 series drive is a very high quality, full featured drive. They have a cut sheet that shows the ratings when powered from a single phase supply. The starting current of the motor isn't a thing with a vfd, because the vfd controls the starting rate of the motor. Look at the FLA of the motor and use that to choose the drive model number. I am using the SJ-P1-0800 20HP 15kW drive to power the spindle on my milling machine. The spindle motors FLA (full load current) rating is 29A. The drives output current rating when powered from single phase is 31A. The power(HP/kW) isn't what determines which drive to purchase. It is the current rating.
I bought the drive from Drives Warehouse website. I got it in a couple days. I'm very happy with the drive and their customer service. They also had the best price.
I bought the drive from Drives Warehouse website. I got it in a couple days. I'm very happy with the drive and their customer service. They also had the best price.
If you have a large 240v circuit, I'd build a rpc(rotary phase converter). Circuit would need to be large enough to power a 20 hp idler for the converter. I like rpc's and have piles of good idlers, wire and disconnects.
Strouty
Well-known member
slodat
ALLIANCE MEMBER
Drive sized for that motor is $1200
Strouty
Well-known member
Price went down, $1044 now.
How long do VFDs seem to last? One of the compressor guys says that he would just use a single phase motor. I like the idea of the soft start, but I am looking at about the same price for a motor and starter as the VFD.
How long do VFDs seem to last? One of the compressor guys says that he would just use a single phase motor. I like the idea of the soft start, but I am looking at about the same price for a motor and starter as the VFD.
forever (almost). i have plenty of freqrol z200 drives at work, manuals look like they were written with typewriters. they run 400 hours/month, and have been for a long, long time. keep them clean and cool and out of sunlight.
Strouty
Well-known member
Good to know, I would assume the hitachi one may even have a leg up over the import cheap ones.
cosmopedro
Well-known member
Guys, I’m sorry I didn’t look through all 780 posts on this thread first, but I’m new to VFD’s and, to be honest, don’t really care to get super-acquainted with them. I’m just trying to run a 200V - 3PH - 5HP Ingersoll Rand compressor motor on single phase power and wondered if this unit:
https://www.ebay.com/itm/274265284519
Would run it? It looks like it would, but like I said I’m new to VFD’s...
Consider the alternative I have set up: a single phase 5HP motor, adaptor plate (since new motor is 56HZ frame and old is 184T) and pulley (old motor 1-1/8” shaft/new motor 7/8”) and magnetic starter... I’m in for about $300-325 that route...
Anyone care to weigh in?
And THANKS ahead of time!
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https://www.ebay.com/itm/274265284519
Would run it? It looks like it would, but like I said I’m new to VFD’s...
Consider the alternative I have set up: a single phase 5HP motor, adaptor plate (since new motor is 56HZ frame and old is 184T) and pulley (old motor 1-1/8” shaft/new motor 7/8”) and magnetic starter... I’m in for about $300-325 that route...
Anyone care to weigh in?
And THANKS ahead of time!
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timgunn1962
Well-known member
In industrial use, the more recent VFDs seem to last "about" as long as the motors they run, in my fairly limited experience.
Where I work, we would "expect" around 5 years of continuous 24/365 operation from a standard motor and around 8 years from a premium motor. In most cases, we have premium motors installed and we run them until they get noisy and/or show high vibration readings using a portable vibration monitor.
Drives tend to be big-name units and are run until they fail: Siemens, Schneider, Emerson, etc.
20 years ago, we were changing out drives more than we were changing out motors and the drives seemed to be lasting about as long as we'd expect a standard motor to last (about 40,000 hours) or a little less.
We had reached the point where we seemed to be changing out similar numbers of drives and (mostly premium) motors a few years ago and we now seem to be changing out more motors than drives.
Many of the motors on some of our older plant are still on Star/Delta (Wye/Delta) starters. Typically these are Hazardous-Area motors that are too big for Direct-On-Line (across-line?) starting. We avoided using VFDs on these for many years because they tended to be much less reliable than Star/Delta. We are now finding that we get better reliability out of VFDs than we do out of the old-school Star/Delta starters.
Where I work, we would "expect" around 5 years of continuous 24/365 operation from a standard motor and around 8 years from a premium motor. In most cases, we have premium motors installed and we run them until they get noisy and/or show high vibration readings using a portable vibration monitor.
Drives tend to be big-name units and are run until they fail: Siemens, Schneider, Emerson, etc.
20 years ago, we were changing out drives more than we were changing out motors and the drives seemed to be lasting about as long as we'd expect a standard motor to last (about 40,000 hours) or a little less.
We had reached the point where we seemed to be changing out similar numbers of drives and (mostly premium) motors a few years ago and we now seem to be changing out more motors than drives.
Many of the motors on some of our older plant are still on Star/Delta (Wye/Delta) starters. Typically these are Hazardous-Area motors that are too big for Direct-On-Line (across-line?) starting. We avoided using VFDs on these for many years because they tended to be much less reliable than Star/Delta. We are now finding that we get better reliability out of VFDs than we do out of the old-school Star/Delta starters.
timgunn1962
Well-known member
I've used a few of the HuanYang VFDs, but never on a hard-start application, like a compressor. There has always been a ramp-to-speed.
Either it'll work fine or it'll struggle to run up to speed.
I'd expect it to just work, but if it struggles to run up, teeing a solenoid valve off the line from the pump to the check valve and switching it through an at-speed-setpoint relay on the drive should work as a pump unloader while the unit is running up to speed and give the drive and motor a much easier time.
Either it'll work fine or it'll struggle to run up to speed.
I'd expect it to just work, but if it struggles to run up, teeing a solenoid valve off the line from the pump to the check valve and switching it through an at-speed-setpoint relay on the drive should work as a pump unloader while the unit is running up to speed and give the drive and motor a much easier time.
cosmopedro
Well-known member
Thanks, timgun1962 - might just be entering the VFD market after all...
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cosmopedro
Well-known member
As an aside (listening, moderator - or GJ app developer?) why do the images sometimes show up and sometimes not...?!?
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whateg01
Well-known member
On compressors, it probably depends a little on the compressor pump. Some pumps won't build pressure until the oil pressure is there. Quincy pumps come to mind. The old t-30 pumps weren't that smart. Not sure on other IR pumps, though.
Dave
Dave
I've had one failure so far (and one pending), failure was DC bus capacitors, and I believe that's going to be the failure on the pending failure as well. the manual claims that DC bus capacitors should last 5 years in an airconditioned office environment. they have lasted far longer in a factory environment.
they're usually electrolytic capacitors, and those are known to age quickly (compared to other more solid state components), and dislike heat.
I would do more to maintain the drives (all i'm doing is replacing fans and cleaning dust out) but I have stock of much better vector VFDs so I'd just as soon replace the V/F drives with "better" ones. not to mention the newer ones are much easier to program/adjust.
has your motor changeout frequency increased? or the drive changeout just grown to match?
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timgunn1962
Well-known member
We're not really seeing any obvious reduction in motor life.
This comes with the big caveat that it's hard to tell for certain because the sample size is relatively small and we're in a business where a lot of stuff gets broken long before it wears out.
We're also running centrifugal blowers in many cases, so going from fixed speed and an adjustable discharge valve to a fully-open discharge valve and (lower, preset) variable-speed. With the variable-torque characteristic of the blowers, this means the motors are doing less work.
Then we have the fact that new motors are not the same as the old motors: newer ones tend to be more efficient, manufacturing locations have changed, etc.
This comes with the big caveat that it's hard to tell for certain because the sample size is relatively small and we're in a business where a lot of stuff gets broken long before it wears out.
We're also running centrifugal blowers in many cases, so going from fixed speed and an adjustable discharge valve to a fully-open discharge valve and (lower, preset) variable-speed. With the variable-torque characteristic of the blowers, this means the motors are doing less work.
Then we have the fact that new motors are not the same as the old motors: newer ones tend to be more efficient, manufacturing locations have changed, etc.
laser3kw
Well-known member
I second that. Our machines run years, being tortured with multiple start / stops, accel / decel every minute.
Key thing with VFD: do not mount them to the machine. The vibration will break parts / circuit boards. Even the cap failure mentioned above was determined to be from vibration (in our machine). We rubber isolate the cabinet if not remove the cabinet from the machine entirely.
Strouty
Well-known member
Good point about the vibration, I will see about mounting our VFD in a enclosure not attached to the compressor.
Do any of the VFDs have provisions for a calculated RPM display? I know you can put a magnetic/hall sensor tach on things to show actual RPMs of an actual spinny bit, but I was just curious if any units have some calculator function build it to either drive like an LED segment display directly or maybe serial or a circuit to send out some calculated pulse count. I know a lot of them provide for a remote potentiometer to set speed but most of the installations I've seen are either using some disassociated tach, or have rigged up some means of being able to see the native display on the VFD (which is in Hz not RPM, so you need to do the math, well every one I've seen) or are effectively just a rough guess with marks next to the dial as to what speed is where.
Surprisingly my Hitachi drives don't, not sure why. I'm sure most any vector drive could do it.
The invertek drives do once you enable slip compensation and feed it all the nameplate data. I have no information on how accurate that is, but probably as accurate as you need it to be unless you need rotary encoder precision.
https://www.invertekdrives.com/clie...Optidrive P2 Advanced User Guide Rev 1.10.pdf
setting P1-10
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hmm, I am really amazed how feature packed some of these units are, those Invertek drives have 3 different choices for remote keypads, and just a ridiculous variety of input and output dohickeys available. But yea, I figured someone needed to be doing that, just seems too obvious.
whateg01
Well-known member
I am building a control box to put on the head of my Newport knee mill. Going to put the speed control knob in the middle of the hub on the switch lever, similar to my Servo power feed. I am in the air about the need, but I have been considering putting together an arduino circuit to take rpm from the VFD and display it.
Dave
Dave
Right, easy enough, if first you have ability to get data, some sort of data from the VFD to do that. I mean even if you had just the ability to get the current Hz frequency of the output this would be somewhat trivial to do. If I know the machine runs at 10K RPM at 60Hz then it's fairly accurate to say it's running at 5K RPM at 30Hz and 15K RPM at 90Hz, yea there is slippage variables but there is slippage variables in just about any sort of belt drive system. So it's probably as accurate as the charts of the mechanical speed settings you are using the VFD to do away with, particularly if that's based on step pulleys or a CVT. But you need that data first, some way, in some form and preferably not by trying to read the cycles directly from the output.
Strouty
Well-known member
My VFD should be here this week, then comes the real questions, I am sure I will post a bit more than usual after it shows up.
timgunn1962
Well-known member
Most of the ones I have used will allow you to select whether RPM or Hz is displayed. The RPM is not usually a precise value: you put in the motor rated RPM at motor rated Frequency (say 1750 RPM at 60 Hz) and the drive displays the speed based on an assumed constant relationship between Hz and RPM (for 1750 RPM at 60 Hz, this would be 29.67 RPM per Hz). It's probably accurate enough to be useful to most of us. Not good enough for an electronic leadscrew, though.
slodat
ALLIANCE MEMBER
What did you buy?
Strouty
Well-known member
The one you recommended.
whateg01
Well-known member
I'm controlling mine via v/hz right now. So, it should be fairly easy to get close. Low frequency operation generally results in loss of torque, so I may still have a need to change pulleys or even use back gear. It would be great to program that in as well so there right correlation is made.