×
INTELLIGENT WORK FORUMS
FOR ENGINEERING PROFESSIONALS

Log In

Come Join Us!

Are you an
Engineering professional?
Join Eng-Tips Forums!
  • Talk With Other Members
  • Be Notified Of Responses
    To Your Posts
  • Keyword Search
  • One-Click Access To Your
    Favorite Forums
  • Automated Signatures
    On Your Posts
  • Best Of All, It's Free!
  • Students Click Here

*Eng-Tips's functionality depends on members receiving e-mail. By joining you are opting in to receive e-mail.

Posting Guidelines

Promoting, selling, recruiting, coursework and thesis posting is forbidden.

Students Click Here

Jobs

Problems on trasformer

Problems on trasformer

Problems on trasformer

(OP)
I have a case on hand: to design a transformer to realize the function that change power from single phase to triple phase, i have no idea on how to figure it out.
I have seen some product on-line which is a static converter, but i am not sure if it's a transformer or some other solutions.

RE: Problems on trasformer

Try a search on "phase converter".  Is this for a rural application?

Will-I-Am

RE: Problems on trasformer

Certainly is not a classic transformer. Transformers modify the voltage but not the phases or frequency.
For an electronic solution, you need a Driver to convert the 1-phase AC to DC and then to 3-Phase AC. Remember that for a true 3 phase system you need three identical AC voltages out of phase 120° electrical one from each other.

For electro-mechanical solution, the only true rotating single phase to 3-phase converter is made with a single phase AC motor driving a synchronous 3-phase generator.

RE: Problems on trasformer

Hello rambozhou

To create the three phase output from a single phase, you are going to need to use a three phase generator. This can take the form of a rotating three phase machine driven by a single phase machine, or a sold state inverter.

It is possible to use a seies of single phase transformers and phase shifting components to generate a three phase voltage, but if you require any "power" from the system, this is not really a practical solution.

For low power requirements with only moderate regulation, you can use a three phase motor driven by a single phase provided that the load is low. You will need to use some means to get the motor to spin to full speed in the correct direction initially.

Best regards,

Mark Empson
http://www.lmphotonics.com

RE: Problems on trasformer

(OP)
Yes, it is accomplished by using phase shifting components (such as capacitor)on the primary side,since the load is 3 phase motor,the current can be balanced only on the full load situation.I have got some information on that in a transformer design book.

Thanks

RE: Problems on trasformer

rambo,
 Is what your proposing supposed to give 120 degree seperation between phases? I doubt it. I have heard of using caps but you never get the 120 degree shift using only caps (correct me if I am wrong).

RE: Problems on trasformer

Check with a company named Ronk. They are the leaders in single phase to 3-phase converters. They have several diferent technologies that you can use:

1. One of them is their Add-A-Phase, which operates a single motor as a permanent split capacitor motor aided by a Steinmetz Balancer Set to get it up to full power. The capacitor in this system is connected to a tapped autotransformer to vary the amount of phase conversion to match the load. The motor serves as a 3-phase voltage source to make the Steinmetz Balancer Set work.

2. They also have a rotary phase converter that also connects the capacitor to a tapped autotransformer to vary the amount of phase conversion when you have a large number of motors turning on and off or which have cyclic loading.

3. Their classic technology is a rotary phase converter with a fixed capacitor, primarily for applications where the motor load is more or less fixed such as a sewage plant.

There is also a thread in this forum where I explain rotary and static phase conversion principles. Most phase converters use both rotary and static principles. This is because you need a 3-phase voltage source to make static conversion to work and a power factor improvement capacitor can use an induction motor's inductance to form a Steinmetz Balancer Set.

Red Flag This Post

Please let us know here why this post is inappropriate. Reasons such as off-topic, duplicates, flames, illegal, vulgar, or students posting their homework.

Red Flag Submitted

Thank you for helping keep Eng-Tips Forums free from inappropriate posts.
The Eng-Tips staff will check this out and take appropriate action.

Reply To This Thread

Posting in the Eng-Tips forums is a member-only feature.

Click Here to join Eng-Tips and talk with other members!


Resources