could you explain what 220-440 v on the name plate of a 3 phase motor means some motors have like 230-460 v some have 208-230/460.
thanks for any info. on this subject

ronald rumfelt

 

When a motor nameplate indicates that a motor is rated 220-440, 230-460, or
240-480, it means the motor is designed to run at either the low or high
voltage rating. The motor nameplate will indicate the connection diagram for
the low or high voltage. 220-240 and 440-480 are nominal voltages. When UL
tests a device rated 220-240 or 440-480, they will always use 240 and 480
volts respectively. 208 volts on the other hand would be tested at 208
volts, because 208 volts is usually not derived by moving transformer taps.
The supply was probably designed for 208 volts to start. If you look at
standard full load current charts, you will see current ratings specified
for 220-240, and a footnote that indicates that current at 208 is 10%
higher, and current at 200 volts is 15% higher.

I hope this is what you were looking for.

 

most 3 phase motors can be wired up as single phase, but in so doing you change the operating voltage. The Plate should have on it a drawing as to how to wire it for single and 3 phase, and what voltages to run at.

Likewise, some motors can be made to run in oposite directions. Again the plate tells how to wire for each direction.

 

Well now, let's keep it nice and simple, a 3 phase motor with these voltage ratings would indicate that depending on how it is to be connected (either star or delta) would dictate the voltage rating. Usually you will find that the Star connection would be the higher voltage rating of the two. Here in the UK, 3 phase motors that are connected to the supply system would be connected in Star for 400v operation in a Direct-On-Line system. The same motor used in another part of the world, the US for example, would be required to be connected in Delta due to the fact that the Line to Line voltage there is 220v.

It is difficult to guage how deep an answer you require but I hope this gives you the basic idea.

 

220-440V on the motor nameplate means that it is a dual voltage motor, meaning you can use it on either 220V or 440V supply voltage, depending on the leads connection, as shown usually inside that motor terminal box cover.

 

could it be the motors can be operated on either of these voltages by connecting the correct input voltage to the appropriate wire taps???

You have probably noticed that there is FLA rating associted with each voltage listed as well, right?

Get some basic electrical knowledge, read a few books. PLEASE!

 

On July 9, 2004, Emery Premeaux wrote:

>most 3 phase motors can be wired up as single phase, but in so doing you change the operating voltage.

I very strongly disagree with this statement. 3 phase motors are just that! 3 phase motors. They should never be used on single phase.
Running a 3 phase on 2 phases is enough to kill the motor.

> The Plate should have on it a drawing as to how to wire it for single and 3 phase, and what voltages to run at.
>
>Likewise, some motors can be made to run in oposite directions. Again the plate tells how to wire for each direction.

Yes all 3 phase motors are reversible but the name plate doesn't tell you which direction they will turn. This is because the phase direction
of the power source is always assumed to be unknown. An electrician is always taught to test the direction of rotation and, if necessary, to
reverse the direction be interchanging any two phases.

Fred Townsend

 

WOW, the level of PLC and computer programing knowledge presented at this forum is impressive but the lack of general basic electrical knowledge by some of the people posting here is downright scary (and dangerous)

A 3 phase 240V/480V motor nameplate means just that, depending on how you connect the windings it can be connected to either a 240V or 480V supply. 208 same thing. For those of you who don't know 208V is 120V 3 phase line to line.

Just about the only thing common between a single and 3 phase motor is that there is a shaft sticking out of the end of the motor that turns. A 3 phase motor is a completely different animal than a single phase motor and you most definately cannot substitute one for the other. To even suggest such a thing in a post is dangerously ignorant.

 

The lower voltage is for when the winding is Delta connected while the higher one is for Star connection.

Gabriel

 

Huh?

Regards
cww

 

Just to clear up a misconception:

A 3-phase motor can be supplied from a single-phase source. Of course, there are limits and constraints that apply!

Regards,
Phil Corso, PE {Boca Raton, FL, USA}
[[email protected]] ([email protected])

 

Are you sure that clears it up? A 3-phase motor can be supplied (and run) from a DC source also, but there is a little more work to be done between the supply and the motor if you want it to produce any torque.

Mark

 

My comment was only to clear up the misconception that it couldn't be done. How, wasn't asked. It is left for the time the question is raised!

BTW, I disagree with your statement about the 'work' needed between the supply and the motor to make it happen. It could consist of as little as a cap or two. And I reiterate, of course, there are limits.

Regards,
Phil Corso, PE {Boca Raton, FL, USA}
[[email protected]] ([email protected])

 

I thought that when the motor is in delta 400v is across each winding (U1+U2, V1+V2 and W1+W2)

In star configaration (U2, V2 and W2 linked out) doesn't the voltage drop, as any two phases have to pass through any two windings in series?

 

Hello,

1. Actually some motor name plate indicate voltage rating as 1ph 220-240VAC/ 50HZ , 1ph 208-230VAC/60hz. Now what does it indicate as frequency is seperate. If we want to measure the RPM at what voltage we should take it?

2. Some fractional HP motors mention 50/60hz both with voltage rating as 220-240V. Here should we measure the RPM 50hz at 220V & 60hz at 240V?

In some motors there is no seperate common wire for 50 & for 60hz supply. Is it recommended to use separate wires for 50 & 60hz. supply?

Awaiting your valuable reply.

 

I have another thought... can a 230/460 3 phase motor run on 208 3 phase?

 

Sure, no problem. In fact, they're typically labelled 208-230/460V.
--
Steve Myres, PE
Automation Solutions
(480) 813-1145

 

Yes, but with some derating. It's better to use the multitapped transformers sold for this purpose and get close. They are often available from surplus dealers very reasonably as a lot of old machines sold worldwide included transformers for matching a wide variety of voltages. They are heavy to ship so they are best purchased locally.

Regards

cww