3 Ph 200v Compressor

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retirede

Senior Member
Location
Illinois
Jraef said:
Before doing anything, go read the actual motor nameplate. This is a somewhat generic drawing package that is adaptable for many options. None of the motor options shown are for 200V, but there is a reference to modifying the thermal trips of the motor protector switch (F1) to a value for 200V. This to me would imply that they are using a motor fully capable of 200-240V, all you need do is tweak the OL protection depending on what you have supplying the machine. This is not an uncommon strategy for OEMs, it reduces the motors they must stock.

So if the motor nameplate does indicate it is good for 200-240V, all you need to do to make it work on 240V is tweak that OL relay setting down a little from the 200V setting.
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Generally speaking, industrial air compressors do not use tri voltage or motors suitable for such a wide range. Customers buy CFM and most compressors using NEMA motors ( 1.15 SF) will load it at 110% of nameplate. Most motors designed for 240 volt systems will not last the warranty period when operated continuously at 110% of nameplate HP on a 208 volt system.

But I do agree - look at the nameplate before spending money.
 
kwired

kwired

Electron manager
Location
NE Nebraska
retirede said:
Generally speaking, industrial air compressors do not use tri voltage or motors suitable for such a wide range. Customers buy CFM and most compressors using NEMA motors ( 1.15 SF) will load it at 110% of nameplate. Most motors designed for 240 volt systems will not last the warranty period when operated continuously at 110% of nameplate HP on a 208 volt system.

But I do agree - look at the nameplate before spending money.
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If this thing runs a lot of air in a plant - it may run continuously, if it is for a EC's shop - it may run very little in comparison to the plant application.
 
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retirede

Senior Member
Location
Illinois
kwired said:
If this thing runs a lot of air in a plant - it may run continuously, if it is for a EC's shop - it may run very little in comparison to the plant application.
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Yes sir, duty cycle is quite relevant. I neglected to mention that.

When I used to run into problems like this, the plant usually had multiple compressors and one (or more) would be running fully loaded while another would throttle or cycle to handle variability of air consumption.
 
kwired

kwired

Electron manager
Location
NE Nebraska
Ingenieur said:
he said it is a 200 v motor (208 nominal)
running it at 240 is not efficient (and will shorten its life cycle)
pretty rare for a motor to be rated 200-230
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You said:
Ingenieur said:
the dwg shows a 440-460 or 220-230 motor?

a 15% buck xfmr should do it

240-208 https://www.schneider-electric.us/en/faqs/FA91925/
what is fla at 200 vac?
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If it is indeed 220-230 volt no buck xfmr needed.

Thread title says 200V, drawings seem to indicate multiple voltages but we don't know if it is easily reconfigured or if they just covered multiple units with the one drawing.
 
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Ingenieur

Senior Member
Location
Earth
kwired said:
You said:


If it is indeed 220-230 volt no buck xfmr needed.

Thread title says 200V, drawings seem to indicate multiple voltages but we don't know if it is easily reconfigured or if they just covered multiple units with the one drawing.
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the dwg does state that
it also states it is set-up for 200
 
Jraef

Jraef

Moderator, OTD
Staff member
Location
San Francisco Bay Area, CA, USA
Occupation
Electrical Engineer
From the "Cowern Papers", discussing motor voltages and designs:

There is one oddity in the mix. That is 3 phase motors for the 120/208 volt power systems. For example,
if the power system were to be 208 volts minus 5% (approximately 198 volts) and you were using a 230
volt motor, then the 230 volt motor could only go down to 207 volts (-10%) without being in trouble.
There would be a discrepancy between the 198 volt low range of the system voltage, and the 207 lowest
operating voltage of a 230 volt motor, this could spell trouble. So how can this be addressed?
There are two ways that motor manufacturers have faced up to the problem. The first is to provide
motors rated for 200 volts that can operate successfully down to 180 volts, or up to 220 volts. This is
an adequate margin to cover the normal range of voltages that could be expected on a 120/208 volt
system. But using this approach exclusively would mean that the complete inventory of motors in all
sizes, enclosures, mechanical configurations, etc. would have to be duplicated to handle the motor
requirements for the 120/208 volt power systems. This would be very expensive and cumbersome,
especially with the wide variety of small motors (under 10 HP) that exist.

So most motor manufacturers have taken a different approach to handling these smaller motors. This
approach is that by using a somewhat more conservative design on the 230 volt motors it is possible to
create a 3 phase, tri-voltage motor with voltage ratings of 208-230/460. With this approach the 230 volt
winding ( and connection diagram) is used on the 208 volt power system. When this approach is taken
the motor manufacturer is essentially saying that this motor can be successfully operated on voltages as
low as 208 minus 10% or 187 volts. This approach usually works very well since 208 volt power systems
are normally used in small buildings with relatively short distances between the incoming power service
and the utilization equipment. These short runs tend to make 208 volt power systems quite stable so that
the limit of the motor’s low voltage capability is seldom tested.
On motors larger than 10 HP the 200 volt motor is generally the best choice, but in many situations 230
volt motors are frequently and successfully applied on the 208 volt systems. In some cases a derate table
is provided for the “low voltage” situation. In other cases the motor service factor may be reduced from
1.15 down to 1.0 when it is applied to a 208 volt power system.
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Now granted, the OP has never divulged the size of his motor, but 67FLA at 200V probably puts is at 25HP. In my experience, a lot of packaged equipment suppliers do indeed use tri-voltage motors, otherwise they must carry more motors in inventory. Despite Cowern's statement about 10HP and below, I built compressor control panels for several compressor suppliers for years and they did it that way on any motor small enough to be offered up for 240V systems (typically 50HP and under) as standard catalog items. One motor for 208-240V supplies, one drawing with multiple setting diagrams for the OLs and (in some cases) the SCPDs.

But again, speculation is pointless, READ THE ACTUAL MOTOR NAMEPLATE!
 
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retirede

Senior Member
Location
Illinois
jumper said:
Yes for the most part. Full 240V 3 phase motors do exist though, not real common IME. I have only hooked up one.
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We used to see specs written to call for 240 or 480 volt motors. Our quote would reply that we will supply "230 or 460 volt motors designed for 240 or 480 V supply". Occasionally, the customer would insist on a motor nameplated 240 or 480. We would call our motor supplier (GE or Westinghouse at the time) and they would take a standard motor and change the nameplate for a price that we marked up and passed on to the customer.

I had always presumed those specs were written by a new engineer just out of school.
 
jumper

jumper

Senior Member
Location
3 Hr 2 Min from Winged Horses
retirede said:
We used to see specs written to call for 240 or 480 volt motors. Our quote would reply that we will supply "230 or 460 volt motors designed for 240 or 480 V supply". Occasionally, the customer would insist on a motor nameplated 240 or 480. We would call our motor supplier (GE or Westinghouse at the time) and they would take a standard motor and change the nameplate for a price that we marked up and passed on to the customer.

I had always presumed those specs were written by a new engineer just out of school.
Click to expand...

Could have been, IDK.

It was a fairly old table saw that the carpenters had at a college I worked for.

Ain't seen another since.
 
Besoeker

Besoeker

Senior Member
Location
UK
jumper said:
Yeah, like all you European people did? 380 to 415.


Oh yeah, I forget- black and blue wire insulation means it is a _______ conductor?

:D
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To 400V actually.
Brown, black, grey for the three phases instead of the simple red, yellow, blue.
Nonsensical in my opinion but that's the stupid, idiotic system we now have.
But I'm just a stupid old fart. Classified as as "thick" by one of your team leaders.
 
Jraef

Jraef

Moderator, OTD
Staff member
Location
San Francisco Bay Area, CA, USA
Occupation
Electrical Engineer
Besoeker said:
Time you guys unified your voltages!!
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What? We ARE "unified".
120/240 single phase for residential
208Y120 3 phase for commercial with primarily single phase loads
240/120 3 phase 4 wire for "light" industrial with primarily 3 phase loads
480Y277 for industrial

What's "un-unified" about that?
 
I

Ingenieur

Senior Member
Location
Earth
Jraef said:
What? We ARE "unified".
120/240 single phase for residential
208Y120 3 phase for commercial with primarily single phase loads
240/120 3 phase 4 wire for "light" industrial with primarily 3 phase loads
480Y277 for industrial

What's "un-unified" about that?
Click to expand...

don't forget
575/3
995/3
:)
 
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