Need Advice on 3kw Regulator Drift

[ETN550]

Just want some of you experts to chime in and let me know if I'm on the right track and should be repairing vs replacing the A1V1 main voltage regulator in the 016E. From the tag on the regulator it does say used on 5kw and 10kw so if common all of you 002 and 003 experts can help too.

This regulator was in a 701A and I swapped it out with a good one from an 016E and now need to fix it or replace it to make the 016E useable.

What it does is after about 5 to 10 minutes of running any load, the voltage drops off until it gets to about 106vac maxed out in the 120 single phase mode. It just slowly starts decreasing and keep going seemingly regardless of heavy or light load.

After it cools off and I restart it will max out at 122 - 125 and then start back down again. This was repeated about 4 times so I became convinced it was being consistent.

I removed the A1V1 regulator and slid the board out and left it hanging by the wires. I only found 2 capacitors on the board.

The appearance of all of the components looks great. No signs of heat or burn marks.

Is there anything else to replace and is the cost of doing a blind replacemnt worth the chance it will solve it?

Thanks for comments and advice.

Doug

 

[Isaac-1]

It is not the same regulator that is used on the MEP-002a or MEP-003a, instead it is used on the MEP-016,017,018 family. I have a similar problem with the one on my MEP-701a, but not as severe, with mine it seems to relate to ambient temperature, on a hot summer day it will max out around 122V, however in the winter it will max out around 130V when in 120V single phase only mode. I have changed out the transistors and seen no change, the next thing I plan to change out are the capacitors.

Hope this helps some

Ike

 

[ETN550]

I'm going to change the two capacitors out and also order an SX460 AVR as Derf and others have made the conversion.

If I make a version of the generator where I eliminate the control box then the small size of the SX460 would really help.

Derf: has the 460 worked okay since you did the conversion?

 

[derf]

I haven't used the gen with the 460 on it. I just did testing. However, my Kubota gen has a similar reg on it and I trust it 100%. They simply use output power to feed DC to the field. You get 1% regulation and under speed (Frequency) shutdown, which is good for running computers and things.

Capacitors are the culprit 99% of the time on things like the VR. Resistors and transistors age and break but they usually just cause the thing to stop working. When capacitors age they can go open or become "leaky" causing their value to fluctuate.

General description
SX460 is a half-wave phase-controlled thyristor type
Automatic Voltage Regulator (AVR) and forms part of the
excitation system for a brush-less generator.
In addition to regulating the generator voltage, the AVR
circuitry includes under-speed and sensing loss protection
features. Excitation power is derived directly from the
generator terminals.
Positive voltage build up from residual levels is ensured by
the use of efficient semiconductors in the power circuitry of
the AVR.
The AVR is linked with the main stator windings and the
exciter field windings to provide closed loop control of the
output voltage with load regulation of +/- 1.0%.
In addition to being powered from the main stator, the AVR
also derives a sample voltage from the output windings for
voltage control purposes. In response to this sample
voltage, the AVR controls the power fed to the exciter field,
and hence the main field, to maintain the machine output
voltage within the specified limits, compensating for load,
speed, temperature and power factor of the generator.
A frequency measuring circuit continually monitors the
generator output and provides output under-speed
protection of the excitation system, by reducing the output
voltage proportionally with speed below a pre-settable
threshold. A manual adjustment is provided for factory
setting of the under frequency roll off point, (UFRO). This
can easily be changed to 50 or 60 Hz in the field by pushon
link selection.
Provision is made for the connection of a remote voltage
trimmer, allowing the user fine control of the generator's
output.

Chinese copies of the Stamford SX-460 are around $60 and seem to be of good quality. I plan to use one with the Yanmar L100 from the 016E I got that was missing some parts and the 017 head I got from Jim to make a nice 5kW set that is relatively portable. It should make a nice big brother to the 016D.

 

[derf]

Here's a video of the 016E running with the 460.

[media]http://www.youtube.com/watch?v=iDDutMmuYcE[/media]

You can see two wires from the output, two wires feeding the field, and two wires shorted together (with the little blue wire nut) that go to the fine adjustment potentiometer. I gutted the box. The adjust pot and a Hardy Diesel meter should complete the necessary controls for me. I won't need the output switch for single or three phase operation, etc.

 

[Isaac-1]

I too have a Chinese 460 clone that I have ready in place to drop into my 701a if the regulator in it fails before I get around to trouble shooting the thermal / volt drift problem. For $60 or so I find it is worth it to have on hand, a number of people have used them on MEP-016 and MEP-017 family of generators (which all share the same shoebox original regulator design) and I have yet to hear a negative comment (other than the poor documentation that comes with them). As to the transistor issue, while it is common for them to result in high or low output voltages, other failure modes exist, for example the MEP-002a I bought a couple of months ago of GL would run fine for about 5 minutes before the voltage would go high, culprit turned out to be the transistor on the voltage regulator.

Ike

 

[derf]

I believe the SX460 is superior to the original MEP VRs and can be used on 1800 RPM and 3600 RPM gens. They seem to be $39 shipped on ebay right now.

And, to clarify, my Kubota has a SE350 VR on the Marathon gen head. It differs from the SX460 in that it only does 190-240 VAC. The Kubota is set up for 120/240 V output, though, and the SX460 would work on it, too.

$40 for a spare universal VR seems like a bargain to me. I have a spare but will probably get another next time I'm buying stuff on ebay.

 

[ETN550]

Thanks for posting the video. I like the simplistic approach. Reduces many failure modes. Nice looking gen set.

I found the trouble shooting section of the manual for the regulator and it is very indepth. I'm going to order a 460 but will also replace the 2 capacitors since I have the shoebox reg apart already.

I was surprised at how the manual goes throught the reg component by component. There is also a pot called r6 in the shoebox that is used to adjust something, maybe would have to do with some of the voltage oscillation we see from time to time. Not sure, the manual really did not say what that r6 pot affected in operation, only how to set it up. There is also a procedure to test the transistors and most of the diodes.

My latest project is to gut one of the Yanmar powered Carver fuel pumps that is housed in the domed enclosure and stuff the guts from a Pow'r Gard into it. I got three of the Carver pumps and they are not selling too well so I am begining to dismantle them and sell off the parts. The Yanmar in them is the baby L40, a 4hp 199cc unit. The housing has 2 inch foam soundproofing all around and it has a solid base, not open like the 701A . The L40 runs exceptionally quiet in this enclosure, so I am hoping the Pow'r Gard will too. I'll get some pics up when it's done. First I'm going to just make all the brackets and such and get it running then I'll strip it all down and paint it nice.