Westerbeke Transformer Regulator KVA

How to get transformer regulator KVA? i need to rewind the transformer, but the electrical workshop need this KVA to quote price. I'm new to this Westerbeke diesel generator. Model is 12 BTDC-514.

Single phase is calculated:
Current in amps × volts ÷ 1000 = kva

3 phase is calculated:
Current in amps × line to line volts ÷ 1000 = kva

Bob Cofer said:

Single phase is calculated:
Current in amps × volts ÷ 1000 = kva

3 phase is calculated:
Current in amps × line to line volts ÷ 1000 = kva

Click to expand...

Is the outcome calculation result is for transformer regulator KVA? The generator is single phase, amps is 52.2 x 230volts ÷ 1000= 12kva. Find attached the transformer picture. Thank you very much.

Ray.Arwin said:

How to get transformer regulator KVA? i need to rewind the transformer, but the electrical workshop need this KVA to quote price. I'm new to this Westerbeke diesel generator. Model is 12 BTDC-514.

Click to expand...

A transformer regulator is a little thing. It can generally fit in the palm of your hand. Maybe a handful but about hand size.

If the transformer regulator in your generator has failed then buy a replacement unit. Its not something you would generally get rewound.

BTW, do you know its the transformer?
More often the bridge rectifier is what fails in a transformer regulator.

If you cannot find a replacement then goto a solid state voltage regulator. There are several off the shelf units that will work, but I really like the Marathon SE350. Basler also makes a great lineup of regulators.

Bob Cofer said:

Single phase is calculated:
Current in amps × volts ÷ 1000 = kva

3 phase is calculated:
Current in amps × line to line volts ÷ 1000 = kva

Click to expand...

3 phase power is calculated as:

Phase to phase volts * amps * the square root of three

In a wye connected system you can also use:

Line to neutral volts * phase A amps
+
Line to neutral volts * phase B amps
+
Line to neutral volts * phase C amps

These calculations result in Volt Amps

To convert volt amps to KVA or kilovolt amps divide by 1000

To convert volt amps to power multiply by the cosine of the phase angle.

12 kva is correct. You may discover that the transformer is marked on the bottom or backside also. Let me do a bit of research and I will get back to you.

Bob

Bob Cofer said:

12 kva is correct. You may discover that the transformer is marked on the bottom or backside also. Let me do a bit of research and I will get back to you.

Bob

Click to expand...

Bob, see my post above, and look at the photo the OP posted.

That IS NOT a 12KVA transformer.

That part is called the compound transformer and does a couple of things. Provides a means of excitation voltage for the generator and through the magic of ohm's law give you the proper output voltage based on how the leads are connected. So it is not just a simple replacement part. Your genset output is indeed 12kva but that transformer is not. You will most likely need to get the OEM part in order to fix it. The information is on page 76 of the Westerbeke Manual but the page is too big to post on this site. Go to westerbeke, marine generators, engines, Official Site and you can download it for free.

Bob

Kevin,

See my post above, you are correct.

Bob

ksanders said:

A transformer regulator is a little thing. It can generally fit in the palm of your hand. Maybe a handful but about hand size.

If the transformer regulator in your generator has failed then buy a replacement unit. Its not something you would generally get rewound.

BTW, do you know its the transformer?
More often the bridge rectifier is what fails in a transformer regulator.

If you cannot find a replacement then goto a solid state voltage regulator. There are several off the shelf units that will work, but I really like the Marathon SE350. Basler also makes a great lineup of regulators.




3 phase power is calculated as:

Phase to phase volts * amps * the square root of three

In a wye connected system you can also use:

Line to neutral volts * phase A amps
+
Line to neutral volts * phase B amps
+
Line to neutral volts * phase C amps

These calculations result in Volt Amps

To convert volt amps to KVA or kilovolt amps divide by 1000

To convert volt amps to power multiply by the cosine of the phase angle.

Click to expand...

I'm not very sure if this is the transformer regulator failure, but i need to check the coil rewinding due to i found corrosion at the transformer steel bar, shims etc and this make me curious about the transformer regulator condition and performance. FYI, in Malaysia its difficult to get the parts and will be so expensive. So, i decided to rewound.

Renewed the bridge rectifier, rewound the main stator and check the fuel pump + governor (still in good condition). Now my problem is, the alternator itself unable to achieve the useable output voltage when loaded. Without load output is 230 volt, loaded only with 1 acu 24,000 btu, suddenly output will dropped to 202 volt. Installed and test with AVR, the output is very constant at 230 volt even loaded with 2 or more acu. But can't afford the AVR cost, hope this make everything clear and i really need some advice on this problem. Thank you.

Download the Technical Manual from the above site. It gives detailed testing parameters and procedures that should help you. You may want to also check the governor for proper performance. Utility power is only required to be + or - ten percent of the nominal voltage and you are outside of that range so there is most likely a problem with the transformer. Did you reinstall the shims exactly as they were removed?

Bob

Bob Cofer said:

Download the Technical Manual from the above site. It gives detailed testing parameters and procedures that should help you. You may want to also check the governor for proper performance. Utility power is only required to be + or - ten percent of the nominal voltage and you are outside of that range so there is most likely a problem with the transformer. Did you reinstall the shims exactly as they were removed?

Bob

Click to expand...

Downloaded and many thanx for the info. The shim is in the correct position, i have added shims to increase the free run output voltage and its work. But still cant achieve the useable voltage. So, now i will rewind the compound transformer and see what is the end result. Back to the earlier question, i still cant get the transformer KVA. Any idea?

Not really. It will be a fractional number at best. Take it in to your rewind shop and they will have to disassemble it and count the windings and wire sizes. Best of luck.

PS Perhaps give technical support a call and see if the information is available?

Bob

Ray.Arwin said:

I'm not very sure if this is the transformer regulator failure, but i need to check the coil rewinding due to i found corrosion at the transformer steel bar, shims etc and this make me curious about the transformer regulator condition and performance. FYI, in Malaysia its difficult to get the parts and will be so expensive. So, i decided to rewound.

Renewed the bridge rectifier, rewound the main stator and check the fuel pump + governor (still in good condition). Now my problem is, the alternator itself unable to achieve the useable output voltage when loaded. Without load output is 230 volt, loaded only with 1 acu 24,000 btu, suddenly output will dropped to 202 volt. Installed and test with AVR, the output is very constant at 230 volt even loaded with 2 or more acu. But can't afford the AVR cost, hope this make everything clear and i really need some advice on this problem. Thank you.

Click to expand...

$50 you can buy a SE350 knock off on ebay.

Thats a pretty versitile regulator and will probably work fine. Download the instruction manual and compare it with the westerbeke spec.

I think the SE350 will do up to 73 volts DC and up to 3 amps

I'd check the spec on the westerbeke exciter and or the westerbeke avr to see if it'll work.

Or better yet research the westerbeke avr and buy a knockoff of that unit.

ksanders said:

$50 you can buy a SE350 knock off on ebay.

Click to expand...

Or, try these guys:

online voltage regulator and static exciter catalog

They offer a huge range of AVRs and exciters, they also have some of the best tech support I have ever had the pleasure to contact and have pulled me out of generator regulation problems in the past. I recommend them without hesitation and suggest calling them for advice.

Forgot to add this link:

http://www.westerbeke.com/TroubleshootingGuides/bt_12_stud_troubleshooting_manual.pdf

RickB said:

Forgot to add this link:

http://www.westerbeke.com/TroubleshootingGuides/bt_12_stud_troubleshooting_manual.pdf

Click to expand...

Yep, my first response when I get a call like this is generally RTFM

ksanders said:

Yep, my first response when I get a call like this is generally RTFM

Click to expand...

I tried that the other day (RTFM on its own line followed by some links) and it got edited out by someone ... at least they didn't delete the entire post that time since it contained some good information.