MEP005A frequency meter not working.

[kloppk]

Correct

 

[yohanusmarcus]

I was afraid you'd say that.
Question if it fails testing is it repairable or replaceable?

 

[Guyfang]

Yes, and yes. Its fixable, if you have the tools and know how. Kurt has made a bomb proof replacement for that card. Do not worry about getting it hooked up right when done. Its not hard. Do take the S/P relay box someplace where you have good light. Do NOT mark the wires. Put them back on using the wire diagram. WHY? Because if someone else hooked it up wrong, you will just repeat the mistake. Trust me. I have done it. When replacing it, the wires almost fall into place. Just LOOK at the wire numbers to be SURE. This is not as hard as you think it is.

 

[Guyfang]

Did speed switch a to b no start but it did crank.

It cant start. When you have just the A&B jumped, it will only turn over the engine, not start. For it to start it then has to reverse the S9-1 contacts, at about 300 RPM.

This below is from the MEP-006 book, but its the same as your set.

14-17. General.
a. The speed switch, driven by the camshaft
through a tachometer drive assembly and an angle
adapter, provides sequenced control of circuits during
engine startup and protection against engine over speed
during operation. Three sets of contact elements, S9–1,
S9-2, and S9–3, contained in the speed switch, are set
to open, close, or transfer by centrifugal force at certain
engine speeds. The speed switch drive gear is designed
to drive the speed switch at one–half engine speed
b. At an engine speed of 580 to 620 rpm (accelerating)
element S9–1 transfers two sets of contacts,
energizing the field flash circuit and de-energizing the
crank relay to stop the starting motor.
On Class 1 sets, when the engine reaches the
speed range of 1180 to 1220 rpm (Mode I); 1650 to 1700
rpm (Mode H) element S9–2 closes, energizing the
electro-hydraulic governor which takes over control of
engine speed.
d. Speed switch element S9-3 consists of two sets
of contacts which are set to transfer at an engine speed
of 2425 ± 25 rpm to shut down the engine and prevent
damage to the equipment. Shutdown is achieved by
de-energizing the stop-run relay and the fuel solenoid,
cutting off fuel to the engine.
2. Elements S9–1 and S9–2 reset at 100 rpm (decreasing)
below actuation speed. Element S9–3 is
manually reset by a push button on the speed switch
housing.

To get the set to run, you need to move your jumper wire on J37, (The S9 canon plug ) from pin A to B, to A to C. Yes, I know the picture shows pin D. Its a TYPO! Pin C!!

 

[yohanusmarcus]

It cant start. When you have just the A&B jumped, it will only turn over the engine, not start. For it to start it then has to reverse the S9-1 contacts, at about 300 RPM.

This below is from the MEP-006 book, but its the same as your set.

14-17. General.
a. The speed switch, driven by the camshaft
through a tachometer drive assembly and an angle
adapter, provides sequenced control of circuits during
engine startup and protection against engine over speed
during operation. Three sets of contact elements, S9–1,
S9-2, and S9–3, contained in the speed switch, are set
to open, close, or transfer by centrifugal force at certain
engine speeds. The speed switch drive gear is designed
to drive the speed switch at one–half engine speed
b. At an engine speed of 580 to 620 rpm (accelerating)
element S9–1 transfers two sets of contacts,
energizing the field flash circuit and de-energizing the
crank relay to stop the starting motor.
On Class 1 sets, when the engine reaches the
speed range of 1180 to 1220 rpm (Mode I); 1650 to 1700
rpm (Mode H) element S9–2 closes, energizing the
electro-hydraulic governor which takes over control of
engine speed.
d. Speed switch element S9-3 consists of two sets
of contacts which are set to transfer at an engine speed
of 2425 ± 25 rpm to shut down the engine and prevent
damage to the equipment. Shutdown is achieved by
de-energizing the stop-run relay and the fuel solenoid,
cutting off fuel to the engine.
2. Elements S9–1 and S9–2 reset at 100 rpm (decreasing)
below actuation speed. Element S9–3 is
manually reset by a push button on the speed switch
housing.

To get the set to run, you need to move your jumper wire on J37, (The S9 canon plug ) from pin A to B, to A to C. Yes, I know the picture shows pin D. Its a TYPO! Pin C!!


View attachment 918720

Guyfang did you say you rebuild the A11s?

 

[Guyfang]

No. Not now anyway. Back in the mid 70's, and it was mostly just replacing parts. Its easy to see whats bad. And 99% of the time it was the card. So we "found" a few bad ones, and ordered "extra" parts to repair them with. Peter has repaired A11's.

 

[yohanusmarcus]

No. Not now anyway. Back in the mid 70's, and it was mostly just replacing parts. Its easy to see whats bad. And 99% of the time it was the card. So we "found" a few bad ones, and ordered "extra" parts to repair them with. Peter has repaired A11's.

I'm pretty sure I need the transformer would you have a line on a replacement?

 

[Guyfang]

Peter did a rebuild thread and wrote what Trafo he bought, because the old one is not to be had. And yes you need one. The good thing, is that the Trafo for the A11 is used in both the 50-60 hertz models as well as the 400 hertz model. Most people think the 400 hertz A11 is junk, and its not. Only the VR card is different. Its closing in on 00:30 here, so if Peter doesn't come up, I can maybe try to start looking in the morning.

 

[yohanusmarcus]

Peter did a rebuild thread and wrote what Trafo he bought, because the old one is not to be had. And yes you need one. The good thing, is that the Trafo for the A11 is used in both the 50-60 hertz models as well as the 400 hertz model. Most people think the 400 hertz A11 is junk, and its not. Only the VR card is different. Its closing in on 00:30 here, so if Peter doesn't come up, I can maybe try to start looking in the morning.

I forgot you don't live in the states have a good nite sir

 

[peapvp]

I'm pretty sure I need the transformer would you have a line on a replacement?

The transformer can be bought via our website
A11 T2 Transformer replacement

The repair of the entire A11 is documented here on this SteelSoldiers thread and starts with post #56 till the end of the thread

 

[yohanusmarcus]

Has anyone seen this
Item description from the sellerItem description from the seller

GENERAL The ADVR-073 is an advance Hybrid Analog Digital Voltage Regulator design for general generating applications. The ADVR-073 uses a reliable electronic chip in its design. This eliminates complex analogue components. In addition, over excitation and loss of sensing shutdown protections with matching U/F, O/E LED indicator lights is standard. Lastly this automatic voltage regulator prevents the generator from excitation overload, preventing excitation and AVR damage. It is easy to install and flexible for use in both shunt type and generators with auxiliary windings. BASIC SPECIFICATIONS ---Voltage sensing: ------170-520, 1 phase, 2 wire ---Frequency: ------50 or 60 hz dip switchable ---Voltage Regulation ------+/- 0.5% ---Power Input: ------Voltage 100-300 Vac 1 phase 2 wire.

 

[peapvp]

Has anyone seen thisView attachment 918986
Item description from the sellerItem description from the seller

GENERAL The ADVR-073 is an advance Hybrid Analog Digital Voltage Regulator design for general generating applications. The ADVR-073 uses a reliable electronic chip in its design. This eliminates complex analogue components. In addition, over excitation and loss of sensing shutdown protections with matching U/F, O/E LED indicator lights is standard. Lastly this automatic voltage regulator prevents the generator from excitation overload, preventing excitation and AVR damage. It is easy to install and flexible for use in both shunt type and generators with auxiliary windings. BASIC SPECIFICATIONS ---Voltage sensing: ------170-520, 1 phase, 2 wire ---Frequency: ------50 or 60 hz dip switchable ---Voltage Regulation ------+/- 0.5% ---Power Input: ------Voltage 100-300 Vac 1 phase 2 wire.

Just another AVR
Same issue as the other AVR, you need a series resistor with the exciter coil
The series resistance must equal 9 Ohm or higher

 

[peapvp]

And here is the manual

 

[yohanusmarcus]

Just another AVR
Same issue as the other AVR, you need a series resistor with the exciter coil
The series resistance must equal 9 Ohm or higher

View attachment 918996

Ok so no better or worse than the 054

 

[Guyfang]

That I would not say. You have to compare what they do, and how they do it.

 

[peapvp]

That I would not say. You have to compare what they do, and how they do it.

That would be correct



the 054 in comparison puts out a max voltage of 63VDC @ 5A continuous into the exciter but can go up to 90VDC @ 7A for up to 10 seconds to accommodate sudden load changes
However the series resistance has to be a minimum of 15 Ohm for the 054

None of the aftermarket AVR’s match the exact DC Field Volt / Current response vs the measured generated line voltage in comparison to the A11 when generator is under load and especially is getting close to 75% to 100% load range

These AVR’s are a compromise when the original A11 is not available any longer

 

[2Pbfeet]

That would be correct

View attachment 919011

the 054 in comparison puts out a max voltage of 63VDC @ 5A continuous into the exciter but can go up to 90VDC @ 7A for up to 10 seconds to accommodate sudden load changes
However the series resistance has to be a minimum of 15 Ohm for the 054

None of the aftermarket AVR’s match the exact DC Field Volt / Current response vs the measured generated line voltage in comparison to the A11 when generator is under load and especially is getting close to 75% to 100% load range

These AVR’s are a compromise when the original A11 is not available any longer

@peapvp Just curious: when you say that the "DC Field Volt / Current response" doesn't match, I think of several possibilities, not all of them bad, or good. Can you elaborate a little? Are they deficient in some way? Is it correctable? e.g. does the DC field signal have more, say for example, jitter in it that impresses harmonics on the output waveform?

Thanks,

2Pbfeet

 

[peapvp]

@peapvp Just curious: when you say that the "DC Field Volt / Current response" doesn't match, I think of several possibilities, not all of them bad, or good. Can you elaborate a little? Are they deficient in some way? Is it correctable? e.g. does the DC field signal have more, say for example, jitter in it that impresses harmonics on the output waveform?

Thanks,

2Pbfeet

Well this is where this starts for beginners:

The exciter coils has a dc resistance of 3 Ohm.
to understand this, the interested reader has to have a basic understanding of ohms law, series and parallel resistance circuits.
Otherwise we are throwing pearls before the swine.

The AVR puts out a maximum of 63V DC to maintain 220VAC between two phases on the output

this equates to a exciter coil current of:

R = U / I

I = U / R

I = 63 VDC / 3 Ohm = 21 Amps

now in the datasheet it tells us that the maximum continues current this puppy can supply at a output voltage of 63 VDC is 5 Amps

this is about 1/5 of current which the excited coil would need

hence the avr is going up in smoke

 

[peapvp]

Now to elaborate a bit further:

any AVR measures the actual AC Voltage the generator puts out on its output terminals usually across two phases

The AVR then adjusts is output voltage, which is DC on the two terminals F1 and F2 and which are sometimes called F+ and F- to which exciter coil of the generator is connected to

This DC Voltage is directly proportional to the AC Output Voltage of Generator and depends with how many DC Volts exciter Voltage 220VAC are achieved which in turn depends on the actual load of the Generator

with a 3 Ohm exciter coil and say a permissible exciter coil current of 2 Amps then the Exciter Coil Voltage would be

U = I * R

U = 2 Amps * 3 Ohm = 6 V

This is about the Voltage the A11 supplies to the exciter coil after the initial Excitation through Start switch with no load on genhead (circuit interrupt open)

The maximum current the A11 can source to the exciter coil is 6 Amps (limited by T2 in A11)

U = 6 Amps * 3 Ohm = 18 VDC

therefor we have to add a series resistor to the 054 F1 F2 Circuit of 12 Ohm for a total of 15 Ohm
3 Ohm + 12 Ohm = 15 Ohm

at 63 VDC the current will be

I = U / R = 63 VDC / 15 Ohm = 4.2 Amps

this results in the following voltages across the exciter coil

U = I * R = 4.2 Amps * 3 Ohm = 12.6 VDC

and across the series resistor:

U = I * R = 4.2 Amps * 12 Ohm = 50.4 VDC

the series resistor needs the following power rating

P = U * I = 50.4 VDC * 4.2 Amps = 211.68 Watt (VA)

plus a hefty reserve since the 054 can putout up to 90 VDC @ 7 Amps for up to 10 seconds

Current at 90 VDC

I = U / R = 90 VDC / 15 Ohm = 6 Amps

Voltage across exciter coil

U = I *R = 6 Amps * 3 Ohm = 18 VDC

Voltage across series Resistor

U = I *R = 6 Amps * 12 Ohm = 72 VDC

Minimum Power Rating of Series Resistor

P = U * I = 72V * 6 Amps = 432 Watt (VA)

I would us a 12 Ohm 500W wire wound resistor

in this setup the voltage and current from the 054 are similar to the A11

But this requires a series resistor

 

[2Pbfeet]

@peapvp Thanks! That was a detailed explanation. I think that I now understand your earlier post. I appreciate you taking the time to explain it.

All the best,

2Pbfeet