Reading a motor plate

[Shaun12]

I was just wondering if you could help me interpret this motor plate? I'm just learning at the moment and as I'm coming across more and more of these I'd like to make sure I'm reading them correctly. Please correct me if I'm wrong - I probably am..

Across the top it tells you it's made by Siemens and is a 3 phase motor, product no. to the right

I'm not sure what the UD 1003 etc no. Is?

Now there seems to be two columns, is it one for 50 hz and one for 60hz?

On the left, runs at 50hz 230 or 400 volts then does it mean 230v connection is delta and star 400v?

It's an .18kw motor full load is .97 A in delta .56 in Star connection, so it won't necessarily run at these all the time.

Cos 0.77 I'm not sure what this means? Something to do with power factor?

1340 rpm

Then has more voltages at the bottom, I'm not too sure why it repeats the information?

Too the right it has to be run at 460v but can be either star or delta

 

[telectrix]

the current is lower in star as the votlage is higher.(P=IV). it's rare to see 230V 3 phase, so it would normally run on 415V ( nominal 400V) connected in star, so that the line voltage is 400V and the phase voltage is 230V ( nominally).

 

[Darkwood]

I was just wondering if you could help me interpret this motor plate? I'm just learning at the moment and as I'm coming across more and more of these I'd like to make sure I'm reading them correctly. Please correct me if I'm wrong - I probably am..

Across the top it tells you it's made by Siemens and is a 3 phase motor, product no. to the right

I'm not sure what the UD 1003 etc no. Is?

Now there seems to be two columns, is it one for 50 hz and one for 60hz?

Yes

On the left, runs at 50hz 230 or 400 volts then does it mean 230v connection is delta and star 400v?

In this case yes

It's an .18kw motor full load is .97 A in delta .56 in Star connection, so it won't necessarily run at these all the time.

This is FLC - Full Load Current the motor will consume while delivering its max 0.18Kw

Cos 0.77 I'm not sure what this means? Something to do with power factor?

Power factor

1340 rpm

Typical 4 pole motor

Then has more voltages at the bottom, I'm not too sure why it repeats the information?

Your voltage may not be exact 230v, you have extra info to give FLC with other voltages.

Too the right it has to be run at 460v but can be either star or delta

No! ... It only shows star as an option the other symbol is not a delta sign its the V for voltage.

Hope that helps

 

[Shaun12]

Thats really helpful guys thanks. I need to read up on power factor as i'm not familiar with it.

I thought it was strange being 230v 3phase. You can run a 3-phase motor on 230v single phase though can't you (with a few mods)?

 

[Darkwood]

Thats really helpful guys thanks. I need to read up on power factor as i'm not familiar with it.

I thought it was strange being 230v 3phase. You can run a 3-phase motor on 230v single phase though can't you (with a few mods)?

Single phase to three phase drives are common which dish out 3ph 230v and this would be one case to delta config' the windings... as for the 1ph to run a 3ph motor directly - I would not go down that road yet until you grasp the basics as you will only start to mix things up and it can get very confusing very quickly, stick to simple 3ph induction motors and the principles to start with then progress to other common motors. Its a very steep hill to climb to get the basics never mind going to advanced theory and practice.

 

[UKMeterman]

Not quite, you would need a motor drive inverter, this would change the 230V ac to about 380V DC then it will chop up the DC to make it look a bit like three phase 230V. You would then use the same motor wired in delta.

 

[Lucien Nunes]

Cos 0.77

That's cos (phi) =0.77, the greek letter phi is used as the symbol for phase angle. The cosine of the phase angle between voltage supplied and current drawn, is numerically equal to the ratio of real power to apparent power (i.e. Watts / VA) which is the power factor. If you know the basics of trigonometry you'll spot that the ratio of wattless power to apparent power will be sin (phi). If not, get a working knowledge and then revisit power factor and suddenly lots of things will become clear.

Its power rating is based on 50Hz, at which it gives 0.18kW which is the modern equivalent of 1/4 horsepower (1hp=746W). However since speed is approximately proportional to frequency, and mechanical power is the product of torque and speed, it can deliver more power at 1650rpm on 60Hz than at 1350rpm on 50Hz. The slip (difference between f.l. speed and synchronous speed) on this motor is quite high at 10% even for 1/4hp, you will find examples that run at up to 1425 rpm and higher still for larger motors.

You can run a 3-phase motor on 230v single phase though can't you (with a few mods)?

I assume you mean without a 1-to-3 phase inverter drive. Yes, you can make it work, by phase-shifting the current in two of the windings with capacitors and in principle this is how a single-phase PSC or CSCR motor works. But the 3-phase motor will never achieve its full ratings as the phase shifts will vary with load, making the flux vector pulsate, unlike on 3-phase mains where it will rotate steadily at constant amplitude at any load. This is why 3-phase induction motors are so much more satisfactory than single-phase.