hi folks, we have got a specific p 1

[Emadshaaban1987]

hi folks,
we have got a specific purpose generator that used for airplanes (3ph 200V 400hz 2400rpm )(houchin aerospace 140kva model c690)
what is the possibility to adapt this generator to be used for domestic purpose (1ph 220v 50 hz)
can the engine speed adapted to give 50hz
do we need to change Engine control module or we need to change the whole alternator with different number of poles ?

 

[itsmoked]

If you slow it enough to produce 50Hz it will only be allowed (without saturating the iron and frying), to produce only 25 volts.

Keith Cress
kcress -

http://www.flaminsystems.com

 

[EdStainless]

It could be re-wound for 50hz single phase, but why not just buy one of those?

= = = = = = = = = = = = = = = = = = = =
P.E. Metallurgy, consulting work welcomed

 

[waross]

That unit has enough iron to produce 20 KVA at 50 Hz. This is related to the V/Hz ratio that is the basis for itsmoked's answer.
Coincidentally that is why 400 Hz has become an aircraft standard. The higher frequency gives an 8:1 ratio weight advantage of the active iron components of motors generators and transformers.
If the generator is connected in delta you may be able to boost the voltage to 43 Volts with a star connection, still with the 20 KVA limit.
A 2400 RPM motor may not be happy running at 300 RPM but with the KVA/kW demand dropped from 160 KVA to 20 KVA, it will probably have enough torque if it is capable of idling that slowly.
You can rewind it for a higher voltage but you will still be limited to about 20 KVA.

But all is not lost.
When you finally get that yacht that you dream about and need a mooring buoy, you have an anchor ready to hand.
Be sure to drain the fluids before re-purposing the unit.

Bill
--------------------
"Why not the best?"
Jimmy Carter

 

[itsmoked]

Alternatively.. Run it as it was designed and feed it to a VFD input then set the VFD in Volts/Hertz mode and feed that into a 50Hz transformer to take 200V to 240V. You can do this up to 140kVA, or up to what you need, or up to your wallet.

If you're more technical you can feed the 400Hz thru a rectifier and dump it onto a capacitor bank. Use a fixed frequency inverter to take that input to 240V 50Hz

Or, transform the 400Hz 200V down to where a solar charger will take the DC and charge a 24V or 48Vdc battery bank. Run a standard inverter system off the 24V or 48V battery bank. They're pretty inexpensive these days and you can use one unit for 1ph, two units for split phase, and three units for 3ph power as desired.

Keith Cress
kcress -

http://www.flaminsystems.com

 

[waross]

The transformer is a good idea. It will take the sharp edges off of the PWM VFD output.
He doesn't need 240 Volts, only 220, 50 Hz.
The unit may go up to 220 Volts without saturating.
Alternately, if the speed can be boosted to 2640 RPM, the AVR may be tweaked for 220 Volts output.
The transformer is a better option technically because of the filter effect.
How will the VFD respond to unbalanced loading?

Bill
--------------------
"Why not the best?"
Jimmy Carter

 

[itsmoked]

I don't think any of the VFDs I generally use care in VHz mode.

Keith Cress
kcress -

http://www.flaminsystems.com

 

[LittleInch]

One of these?

http://www.exprom.pl/c690.pdf

You want a 140kVA single phase 220V supply??

New generator required.

Remember - More details = better answers
Also: If you get a response it's polite to respond to it.

 

[waross]

One of these?

http://www.exprom.pl/c690.pdf

You want a 140kVA single phase 220V supply??

New generator required.

If you can find a single phase generator at above 15KVA to 25 KVA, it will be a reconnected three phase generator.
There are a number of ways to reconnect a three phase generator for single phase.
A delta connection.
A double delta connection.
A zig-zag connection.
A bar-diamond or Collins connection.
Abandoning one phase of a wye connected generator.
A transformer with the secondary windings connected in one of the above configuration.
The KVA rating of a single phase connection is always 2/3 of the three phase KVA rating.
The kW capacity is the same as the KVA capacity with a PF of 1.0 rather than the PF of 0.8 that is almost universal for three phase generators.
There may be some exceptions to the kW rating, particularly in military sets.
Commonly orders for larger single phase sets are filled by reconnecting a three phase model set.
When faced with an order for a large number of similar sets such as a military order, a set builder may opt to take advantage of the reduction in capacity to fit a prime mover of less capacity.
Your 140 KVA rating will drop to 93 KVA.
Bill
--------------------
"Why not the best?"
Jimmy Carter

 

[itsmoked]

and... rectifying it all to DC and synthesizing single phase are all ways of NOT "New generator required."

Keith Cress
kcress -

http://www.flaminsystems.com

 

[waross]

I like that, Keith.
That way you don't take the automatic 1/3 capacity hit that the various connection schemes entail.

Bill
--------------------
"Why not the best?"
Jimmy Carter

 

[itsmoked]

Thanks Bill.
Your list boggled my mind about the ways to hack a generator. Had no idea there were that many ways.

Of course, the synthesizing method has an efficiency hit but these days it's not very much.

Keith Cress
kcress -

http://www.flaminsystems.com

 

[waross]

Of course, the synthesizing method has an efficiency hit but these days it's not very much.

Actually the gross losses may be much less than you suppose.
The internal losses in the generator that are avoided with your inverter solution are much greater than you realize.
kW vs KVA in a Zig-Zag connection.

With the sample 10 kW load on 240 Volts, the current will be 41.7 Amps in all windings.
One winding is at 50% PF lagging and another winding is at 50% PF leading.
That accounts for the extra KVAs.
There is no free lunch.
Any re-connection for single phase will run into the extra 50% of internal losses.
Avoiding those extra reconnection losses will probably more than offset the inverter losses.

Next chapter why I prefer a zig-zag connection for field conversions.

Bill
--------------------
"Why not the best?"
Jimmy Carter

 

[waross]

Why the zig-zag connection is the best easiest and quickest for field conversion from three phase to single phase.
Working in the field it is always a good day when the wire markings on a motor or generator are pristine.
Clean, clear and legible.
That is not always the case.
On older machines we encounter dirty wire tags. Faded wire tags. Missing wire tags. Tags that are illegible for any reason.
Reconnecting becomes a challenge.
The majority of three phase generators of the size that are most likely to be converted to single phase are wye connected for 120/208 Volts.
There are six windings.
There will be three line connections and a neutral connection in the motor JB.
Step one: Open the neutral connection.
Step two: With any type of continuity tester, identify the neutral ends of the windings from any line connection.
Step three: Connect those neutral ends to any other line connection.
Insulate that connection and forget it. You will never need it again.
Reconnect the other four neutral leads.
You are finished.
It doesn't matter which phase windings you start with.
It doesn't matter which line you connect to as long as the winding is not connected back on itself.
One line connection has been taped up and put aside.
You now have two line connections and a neutral connection.
From line to neutral to line you will have center tapped single phase with no phase displacement.
Where some numbers missing or illegible? Didn't matter.
The KISS principle reduced to the simplest.

Bill
--------------------
"Why not the best?"
Jimmy Carter

 

[itsmoked]

oh kaaaaaaaay.. I'm a visual guy so it's not easy for me to visualize this.. I'll have to think about it. Thanks Bill.

Keith Cress
kcress -

http://www.flaminsystems.com

 

[waross]

Bill
--------------------
"Why not the best?"
Jimmy Carter