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I've sorted it folks. gotta use input power and not output power. Recalculating gives me Input real power = 305W (not 180W as on nameplate), apparent power = 401.8VA and reactive power = 261.6VAr. Now when plotted I get an angle of around 40 degrees which is 0.76 power factor. Great, thought I...

Chaps, Is it possible to calculate the VA (apparent power) and the VAr (reactive power) of a three phase induction motor by using information from the manufactures data sheets? I've tried it but must be doing something wrong because when I plot these values on a power triangle I'm getting a...

Totally agree with Waross's last post. Over and above what is required, very refreshing. That goes for all the regular posters here by the way. Super helpful forum.

Thanks for that Scotty. This came up in a conversation with a colleague. I kind of suspected that the letters might be just a manufacturers reference but wasn't sure.

Was just wondering if anybody knew what the first three letters stand for: NIT20M25, TIA32M40, TIS63M80 or has it been lost in the midst of time?

Thanks for that chaps, I kinda suspected what you said, just wanted to be sure.

I have a question regarding dual voltage motors. Commonly 3 phase low voltage motors sold today (in Europe) are specified as 230/400v delta/star. According to my understanding if this motor was installed in the UK it would have to be configured to run in star. If it were configured to run in...

Most probably refering to max interruption capabilities: 16A for resistive load, 2A for inductive load.

This post is a little off topic but it is concerning the linked website mentioned in arrehman1 post. I was impressed with the drawing package used in the tutorial videos and as I have a need for such a tool I was wondering what it is called. Thanks

Thanks for that jraef

Chaps, just a quicky. Am I right in thinking that on a three phase motor's nameplate the full load amps is refering to the current drawn on each individual phase? Thanks

Hi Chaps I have a small test rig consisting of an SLC-500 rack, a small three phase motor driven by a VFD, and an optical sensor reading a slot in a disc mounted to the motor shaft. I have written a small ladder program to count the pulses for a period of time using a free running timer then...

Hi All I teach at an engineering academy and one of the courses we offer is an introduction to PLC's. I have 8 Allen Bradley SLC-500's and use 8 paid for licences of RSLogix version 7.30.10. I recently obtained a budget to upgrade our old desktop PC's and specified Windows 7 operating system...

Thanks for the explanations chaps, darn that pesky leakage reactance.

I wanted to demonstrate the voltage phase shift between primary and secondary on a three phase transformer so I had one built by a local company. All the winding ends are accessible so I can configure it any way I please. When connected up as star-star I expected there to be no phase shift but...

Well on the test motor I jut tried putting some load on the shaft and sure enough the displacement between voltage and current fell from 4mS to 3mS that equates to a change in power factor from 0.3 to 0.59. Still some way off the quoted nameplate value of 0.77 but getting better and proving that...

I have a small three phase test motor and on the nameplate it gives a power factor of 0.77. This equates to an angle of around 45 degrees. I hooked the motor up to an oscilloscope and measured around 4mS difference between the voltage and current. Four milliseconds equates to around 72 degrees...

Hi Chaps I know that the power factor in a system is the ratio of KW to KVA but is it also true that the power factor equals the cosine of the angular displacement of voltage to current in a reactive circuit? Thanks

It's ok I made a fundamental error. Measured the resistance of the coil wrongly, should be 50 ohms not 2 ohms.

I’m doing a simple experiment to measure the ac current thru a coil and I’m getting nowhere close to the calculated values. The coil is hand wound and has a value of 57mH when measured by an LCR meter. It also has a resistance value of 2.61ohms measured by the same meter. My power supply is...