Heritage: Early 20th century power generation 1

[Vegemite]

Dear Heritage Buffs, I am reading a report from 1912 in which the author is comparing rotary converters with motor-generator sets for the conversion of 440 V AC to 600 V DC for tramways use. Can you please explain the difference? In another report the DC power stations of that time are said to have an electrical machine described as a 'balancer'. Could you please help with this as I can find no description of this device?

 

[waross]

Driving with induction motors rather than synchronous motors would make synchronizing a little easier. You wouldn't have to slip poles as the induction motor is already slipping poles.

Bill
--------------------
Ohm's law
Not just a good idea;
It's the LAW!

 

[crshears]

Exactly.

CR

"As iron sharpens iron, so one person sharpens another." [Proverbs 27:17, NIV]

 

[Sparweb]

A Rotary Converter is a device that shares a rotor with both the AC circuit and the DC circuit.

And it works the other way, too. A rotary inverter from a wartime aircraft that converts 28VDC into 120VAC Delta at 400 Hz sitting in a forgotten corner of my garage. I dunno what to do with it really.

Please remember: we're not all rednecks!

http://www.sparweb.ca

 

[cranky108]

What in the world would you do with 400Hz?

That said, the old power system analizers,used 400Hz, likely to make things smaller.
This was before computers, so the 400Hz was fed into the generator units, where the field was the single phase output to the other parts of the wired network.
These were wired like the network (grid), with matching line, transformer, and load units, so that a load flow model could be run.
The generator units could be shifted in phase angle and voltage to make the flows in model as observed.

I have never seen one work, but the university I attended, years ago, had one, complete with a 60Hz-400Hz MG set.

 

[waross]

400 Hz is a standard aircraft frequency.
1 KVA, 50 Hz equipment may be pushed to 8 KVA at 400 Hz.
Motors, generators and transformers are much smaller and lighter for a given capacity.


Bill
--------------------
Ohm's law
Not just a good idea;
It's the LAW!

 

[cranky108]

I know that 400Hz is used for aircraft, but unless you have an aircraft, what would you use it for?

 

[waross]

The owner:

SparWeb (Aerospace)

Bill
--------------------
Ohm's law
Not just a good idea;
It's the LAW!

 

[zeusfaber]

What else would you use 400Hz for? Providing an excitation source for synchros springs to mind (thank you for reminding me how much I hate those things).

And don't try running that inverter up without decent hearing protection (they scream like a banshee).

My first "LAND AT ONCE" - OK, that field, there, now. Was when one of those inverters packed up.

A.

 

[Sparweb]

ZF,
I have, you're right, it's loud.
I also got a cute little aircraft oil cooler fan motor to run off of it.
There wasn't much point of doing this, I admit.
Maybe the local aero museum will have some use for it.

Please remember: we're not all rednecks!

http://www.sparweb.ca

 

[crshears]

400 Hz was, and in some cases still is, used to supply power to the magnetic amplifiers controlling unit excitation in generating stations of that 1950s/1960s vintage.

CR

"As iron sharpens iron, so one person sharpens another." [Proverbs 27:17, NIV]