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question for the electrical engineering types = VFD 3 phase stuff


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1 hour ago, hardtail said:

Our building air conditioning compressors run at 35000 rpm, magnetic levitation 

Theres no levitation here my butts too heavy more like my jd A WOT 900 rpms 

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if any of you are looking for a quincy 325 or 350 there are a couple for sale our near manhattan ks on equip bid - i have one of those old beasts will have to get a pic of it on here 

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Gosh I didn't realize a 5hp single phase motor was nearly that expensive these days! 

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They have really gone up in the past few years, same Baldor spec we just purchased was over $1K up here a couple weeks ago, availability sometimes an issue also 🥺

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19 hours ago, hardtail said:

Our building air conditioning compressors run at 35000 rpm, magnetic levitation 

Last place I worked at in IT had  racks full of hard disks that ran at ~12,000 RPM trouble and vibration free for around 5 years.  They all spun on very low friction magnetic bearings, I have been out of the loop for years now and did not realize that, that type of suspension had spilled into mainstream applications.

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An open motor vs totally enclosed fan cooled (TEFC) is worth consideration. Dirt and condensation are a factor in shop situations.

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35 minutes ago, just Dave said:

An open motor vs totally enclosed fan cooled (TEFC) is worth consideration. Dirt and condensation are a factor in shop situations.

yes dave that is what the baldor engineer said - he said life in exposed open motor = cheaper = life span 3-5 yrs - the farm duty enclosed motors they make he said 15 to 20 - he said if you can afford it do the farm duty they are built tough 

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On 6/8/2022 at 1:22 PM, searcyfarms said:
On 6/7/2022 at 11:07 AM, jeeper61 said:

funny you picked that motor its the one the baldor tech/engineer guy told me to get, the farm duty has a lot more starting torque and he said unless youknow for sure the device will take the start torque you might be wise not to risk it - the farm duty line is nearly double the start torque

This looks like an open motor to me. My mistake?

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11 minutes ago, just Dave said:

This looks like an open motor to me. My mistake?

yes he gave me the farm duty one spec'd and its about 1000 to 1200 more 

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Maybe I am over simplifying this but why couldn't you just wire the pressure switch to the input side of the VFD and then wire the vfd directly to the compressor motor?  Set the VFD to soft start when it is powered on that way you won't overload it at startup.

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i dont have a VFD i ordered a DPS = phase shifter and it hasnt arrived yet - you guys can tell me how to wire it then 😉 cause i will forget between now/then, its of course In The Mail!!!

@ZG6E

 

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2 hours ago, searcyfarms said:

i dont have a VFD i ordered a DPS = phase shifter and it hasnt arrived yet - you guys can tell me how to wire it then 😉 cause i will forget between now/then, its of course In The Mail!!!

@ZG6E

 

The DD-963 class of ship I was on in 1983 was producing 400HZ power with  solid state 3 phase inverters they failed more often than the old style motor generators sets (3% 60 HZ motor driving a 3% 400 HZ generator) but were only about the size of a 25 CF refer, made no noise except for cooling  fans running. It was NOT a simple phase shifter. It converted 3% 60 HZ into DC and the DC back to properly phased and regulated 400 HZ 3%. They were around 125 KW 3% 400HZ output.  Many taxpayer $$ spent on one of those. 

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3 hours ago, searcyfarms said:

i dont have a VFD i ordered a DPS = phase shifter and it hasnt arrived yet - you guys can tell me how to wire it then 😉 cause i will forget between now/then, its of course In The Mail!!!

@ZG6E

 

I am truly interested in your phase shifter. Seems like they would be great if they hold up. From looking at the compressor pic, you would not wire it to the pressure switch. You will probably wire the phase shifter in between the motor starter and the motor. You will likely need to change heaters in the starter, assuming that it is a NEMA starter or adjust the settings on an IEC starter. I can't tell what is inside your box. Post some pictures of the inside of the starter. 

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8 hours ago, 12_Guy said:

I am truly interested in your phase shifter. Seems like they would be great if they hold up. From looking at the compressor pic, you would not wire it to the pressure switch. You will probably wire the phase shifter in between the motor starter and the motor. You will likely need to change heaters in the starter, assuming that it is a NEMA starter or adjust the settings on an IEC starter. I can't tell what is inside your box. Post some pictures of the inside of the starter. 

if i only had a DD-963 around here id be set ? do you guys deliver? 

sure enough i can do that tomorrow i been out working on orings and valve on the john bean and got 6 tires dismounted and 4 mounted and it tested out ok, im not really fast using it yet but boy it sure works slick!!!

got church at 0800 - small group from 0930 to 1230 - will have till 1430 to look at the compressor stuff then got a meeting about our blended family class we will be doing this fall - stay tuned more exciting sparks ( or smoke hopefully not ) to come 

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@searcyfarms

Google the DPS phase shifter. The company has a few videos on wiring and operation. It appears that motor starting is inherent in the unit. Unfortunately the translation and sub titles are a little awkward. Make sure the circuit breaker is sized right at twice the rating of the motor. 30 amp probably and wire is correct gauge, 10 minimum. Read all instructions. You might want to remove the compressor belt and check operation and rotation for initial start up. I hope this works!

The one I used didn’t have much of a load and worked fine.

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33 minutes ago, TomH said:

@searcyfarms

Google the DPS phase shifter. The company has a few videos on wiring and operation. It appears that motor starting is inherent in the unit. Unfortunately the translation and sub titles are a little awkward. Make sure the circuit breaker is sized right at twice the rating of the motor. 30 amp probably and wire is correct gauge, 10 minimum. Read all instructions. You might want to remove the compressor belt and check operation and rotation for initial start up. I hope this works!

The one I used didn’t have much of a load and worked fine.

its here !!! i didnt have time to futz with it yesterday has mowing duty, 85th bday for the MIL, rebuilt one of the pedals on the tire machine, worked on 6 of the neighbors tires and got him going - today i hope to send pix of the box on the compressor where the wires go in - then wait for you guys to encourage me in how i shoudl wire it, i have looked over the instructions and so far it seems easy enough and wiring with direct or mag starter for the motor 

it says I did perfect in upsizing one size for the phase shifter vs motor size so so far so good per instructions - stay tuned for more pix 

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4 hours ago, TomH said:

@searcyfarms

Google the DPS phase shifter. The company has a few videos on wiring and operation. It appears that motor starting is inherent in the unit. Unfortunately the translation and sub titles are a little awkward. Make sure the circuit breaker is sized right at twice the rating of the motor. 30 amp probably and wire is correct gauge, 10 minimum. Read all instructions. You might want to remove the compressor belt and check operation and rotation for initial start up. I hope this works!

The one I used didn’t have much of a load and worked fine.

 

On 6/11/2022 at 12:40 PM, oleman said:

The DD-963 class of ship I was on in 1983 was producing 400HZ power with  solid state 3 phase inverters they failed more often than the old style motor generators sets (3% 60 HZ motor driving a 3% 400 HZ generator) but were only about the size of a 25 CF refer, made no noise except for cooling  fans running. It was NOT a simple phase shifter. It converted 3% 60 HZ into DC and the DC back to properly phased and regulated 400 HZ 3%. They were around 125 KW 3% 400HZ output.  Many taxpayer $$ spent on one of those. 

 

On 6/11/2022 at 9:22 AM, ZG6E said:

Maybe I am over simplifying this but why couldn't you just wire the pressure switch to the input side of the VFD and then wire the vfd directly to the compressor motor?  Set the VFD to soft start when it is powered on that way you won't overload it at startup.

Well i got my theory how to do whatta you guys think? 

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This should be pretty easy. Wire your 240 volt input to the left two terminal on top. Output to the DPS is from the bottom left two terminals. I would recommend pulling the wires off of the bottom and connect them to the DPS output. Then install jumpers between the starter and the DPS input. It should be installed in a metal box. I don't know if there will be room in this box. Lastly you will likely need to increase the heater size. There should be a number on the bottom of the heater in the marked area below. There hopefully is a chart inside the box to help select a new size. You can probably start with adjusting the "Pacman" shaped dial on the right side of the overload assy. Turn it all the way down to +15%. That really isn't enough extra capacity but you may get by depending upon how hard you run the compressor. Unfortunately the contactor is probably undersized now because of the extra load. 1ph load will be higher than the 3ph load. 14amp compressor FLA x square root of 3 (1.73) = 24.25single phase amps. This should be close. The contactor is rated at 25FLA. The amp draw will change as the pressure builds up. Many compressor manufacturers intentionally overload the motor as the pressure is nearing shut off pressure.

I hope this helps and that it works well for you. 20220612_155553.thumb.jpg.5cc0f6ed75c7648480766ffc8b83c4cb.jpg

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2 hours ago, 12_Guy said:

This should be pretty easy. Wire your 240 volt input to the left two terminal on top. Output to the DPS is from the bottom left two terminals. I would recommend pulling the wires off of the bottom and connect them to the DPS output. Then install jumpers between the starter and the DPS input. It should be installed in a metal box. I don't know if there will be room in this box. Lastly you will likely need to increase the heater size. There should be a number on the bottom of the heater in the marked area below. There hopefully is a chart inside the box to help select a new size. You can probably start with adjusting the "Pacman" shaped dial on the right side of the overload assy. Turn it all the way down to +15%. That really isn't enough extra capacity but you may get by depending upon how hard you run the compressor. Unfortunately the contactor is probably undersized now because of the extra load. 1ph load will be higher than the 3ph load. 14amp compressor FLA x square root of 3 (1.73) = 24.25single phase amps. This should be close. The contactor is rated at 25FLA. The amp draw will change as the pressure builds up. Many compressor manufacturers intentionally overload the motor as the pressure is nearing shut off pressure.

I hope this helps and that it works well for you. 20220612_155553.thumb.jpg.5cc0f6ed75c7648480766ffc8b83c4cb.jpg

ok i noticed the +15% adjustment on the side of the contacter/heater ? wasnt sure the actual name

next when i open up the motor to figure out what the red/black/white wires are hooked to inside the motor will it be like the letters on the DPS U-V-W ? I suppose I will have to find a box to try to put all this in somewhere but for testing it will be temp - the air compressor will not get HEAVY use like all day long, just when I paint something or run some air tools likely the longest it would be running would be 10 mins at a time and shut off and maybe like a couple hours at most on a weekend 

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The adjustment should be for the overload . It gives you some adjustments for motor load under varying conditions.

Connect the 3 leads from the motor to the U V W and check rotation. Switch 2 wires as indicated in the instructions if it runs backwards.

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1 hour ago, searcyfarms said:

ok i noticed the +15% adjustment on the side of the contacter/heater ? wasnt sure the actual name

next when i open up the motor to figure out what the red/black/white wires are hooked to inside the motor will it be like the letters on the DPS U-V-W ? I suppose I will have to find a box to try to put all this in somewhere but for testing it will be temp - the air compressor will not get HEAVY use like all day long, just when I paint something or run some air tools likely the longest it would be running would be 10 mins at a time and shut off and maybe like a couple hours at most on a weekend 

I would start at the full +15% set point. It may work fine for limited use. 
The bottom black device is the overload assembly. The vertical metal strips are the heaters. They are available in different size ratings for different motor amperages. The black device on top is the contactor. It’s a heavy duty relay that connects the power to the motor. The complete assembly - contactor + overload is considered a motor starter. 
I would unhook the wires to the motor from the overload and move them to the DPS. Then add some jumper wires between. This way you don’t have to mess around with the motor. 
On second thought, are you certain that the motor was used on low voltage power 208-240volt? Not 480??? It might be wise to open up the motor box and count wirenuts. There will be 4 for 240 volt and 6 for 480volt not counting the ground connection. 

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50 minutes ago, 12_Guy said:

I would start at the full +15% set point. It may work fine for limited use. 
The bottom black device is the overload assembly. The vertical metal strips are the heaters. They are available in different size ratings for different motor amperages. The black device on top is the contactor. It’s a heavy duty relay that connects the power to the motor. The complete assembly - contactor + overload is considered a motor starter. 
I would unhook the wires to the motor from the overload and move them to the DPS. Then add some jumper wires between. This way you don’t have to mess around with the motor. 
On second thought, are you certain that the motor was used on low voltage power 208-240volt? Not 480??? It might be wise to open up the motor box and count wirenuts. There will be 4 for 240 volt and 6 for 480volt not counting the ground connection. 

more to come on this adventure when i open up the motor cover - I am not sure what 3 phase voltage it was using im sure we talked about it in the conversation at some point but ive got 37 irons in the fire right now and cant quite remember - thats why i said i would be looking inside where teh motor cover to see what is going on in there - thank you guys for bearing with me while I try to grasp more knowledge - shoving things into my old brain are getting harder and harder it seems 

i will try look at the wiring at least tomorrow after work, i got the tire machine going and balancer works too = YAY 

 

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12 hours ago, 12_Guy said:

I would start at the full +15% set point. It may work fine for limited use. 
The bottom black device is the overload assembly. The vertical metal strips are the heaters. They are available in different size ratings for different motor amperages. The black device on top is the contactor. It’s a heavy duty relay that connects the power to the motor. The complete assembly - contactor + overload is considered a motor starter. 
I would unhook the wires to the motor from the overload and move them to the DPS. Then add some jumper wires between. This way you don’t have to mess around with the motor. 
On second thought, are you certain that the motor was used on low voltage power 208-240volt? Not 480??? It might be wise to open up the motor box and count wirenuts. There will be 4 for 240 volt and 6 for 480volt not counting the ground connection. 

so how does the heater work, i presume if it gets too hot, distorts or causes something to spring away and lose contact like a set of points or something ? 

what if only one leg were to disconnect and the other two stay engaged ? or does it trip out ALL connections ? I would presume so. 

Interesting and learning a lot never seen a motor starter like this, all I have ever seen are the start winding centrificual force clutches and start caps for starters before. 

any idea how HOT temp wise these things run at or get before kicking out? 

 

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