Power Equipment Forum banner

1 - 13 of 13 Posts

·
Registered
Joined
·
93 Posts
Discussion Starter #1
Does anyone have a schematic of the board located in the lower left corner of a Briggs Stratton transfer switch?
The board has the following numbers on it:
Daco 0323
B29909A
I plan to map the inputs but weather is prohibiting my doing that at present.
Even if I map the inputs I am at a loss of the function of the board without a schematic.
 

·
Registered
Joined
·
426 Posts
Does anyone have a schematic of the board located in the lower left corner of a Briggs Stratton transfer switch?
The board has the following numbers on it:
Daco 0323
B29909A
I plan to map the inputs but weather is prohibiting my doing that at present.
Even if I map the inputs I am at a loss of the function of the board without a schematic.
What is the actual B&S Model Number for your Transfer Switch? With that in hand, hopefully can find the documentation...

Some of the possible model numbers are: 071100 071150 071200 01918 071075 071047 071076 071071 071070 071068 071054 071057 071038 071055
 

·
Registered
Joined
·
93 Posts
Discussion Starter #3
Tabora, I appreciate your response as in searching the forum I have noticed you are the man in the know, so here goes:
First I have no formal training in Briggs Stratton generators, just a 35 year background in Industrial electronics and electrical.
This transfer switch is an older model. Maybe 20+ years old. I did not notice a model number inside the switch, but I will revisit the unit on Friday and search the unit for the number weather permitting.
It is paired with a Briggs Stratton model 1931-0 10 KW standby generator. (Neat little 40 amp generator)
I have managed to get schematics from the Sears parts website and other sites.
The generator began to give trouble starting.
I traced the problem to the starter contactor.
Once I replaced the contactor the generator starts and runs great when utility is removed.
The problem I encountered is that it fails to stop once the utility is restored.
The transfer switch board in question has two Light emitting diodes, one red and one green.
Numbers on the board are as I mentioned in the above post and both LED's are on.
Of the two contactors in the transfer switch, the generator relay (E) on the print stays energized and fails to drop out once utility is restored.
I have a new internal generator board (Cost $330.00) and I am going to swap it out.
Pins 17 and 18 are the ones that latch in once the generator generates 240 vac power, drops out the starter relay and holds in gas flow which will remain energized keeping the generator running.
Pins 15 & 16 get their power once utility is restored, and to my idea they should cause the board to stop fuel flow and allow relay (N) in the transfer switch to drop out. This however is not happening.
But the LED's are bugging me being both on, but maybe they should be on if utility and generator are supplying voltage to the little board.
The board in question is available for $185.00, but before I add another cost I need to get my ducks in a row.
It should be noted that this generator belongs to a friend whose wife has Alzheimer's and I offered to try to repair it if I could @ parts cost only.
Your help is most appreciated.
 

·
Registered
Joined
·
93 Posts
Discussion Starter #5
Tabora, you are correct and I have that schematic.
I have poured over it carefully.
There are no notations on the Switch gear schematic that identifies the 240 vac that supplies the transformer that feeds 24 vac to the generator board that signals the generator when utility is lost and later restored.
Now after thinking about this, I must go back and look and see if the utility feed is somehow connected to the 24 vac transformer and I failed to make a better analysis.
I need a better understanding this part of the wiring.
I am thinking the connections are OK, but for some reason the generator board has lost its ability to de-energize the gas valve.
I will swap out the generator board and see where to go.
If that generator were in my back yard I would have a better opportunity to solve its problems.
I appreciate your help and I will post my findings once I solve the problem.
 

·
Registered
Joined
·
93 Posts
Discussion Starter #7
I took a look at the install info and continued to page 8.
There on the diagram was the answer to what I had been missing.
Two lines are shown leaving the two fuses and going to the generator.
I had seen this info but failed to notice the two lines shown.
Those feeds are the ones that go the 24 vac transformer that signal the generator board that the utility is either lost or back on.
That info solved a missing piece of the puzzle.
I will start at this point today as the weather is going to be dry and in the high 50's.
I called the owner and told him I would be there as the transfer switch is in the locked garage.
Thank you Tabora, I will let you know later if the issue is resolved.
 

·
Registered
Joined
·
93 Posts
Discussion Starter #8
First off, you may notice a post that was delayed due to my being new to the forum.
Please ignore it.
So today I returned to map the wiring to see if I had a full understanding of the circuits.
Everything was as described in the schematics and correct.
I took note of the transfer switch numbers: 185891 Manufacture date 03/02/96.
Once I was sure the wiring was as described I set about to swap out the Generator board.
I am so sure I have the problem isolated.
Fifteen minutes and I have it done.
I removed utility voltage and watch as the N relay drops out.
Fifteen seconds and the little generator starts.
I wait for a few seconds and the (E) relay picks up restoring power to the circuits.
So far so good.
Now to re energize the utility circuits.
Done! Nothing happens. The generator keeps purring and the (E) relay stays energized.
I wait, finally I go out and turn the control switch to off. The Generator stops.
Then I few seconds I return the control switch back to auto.
To my surprise the generator re starts.
I put the control switch back into the off position.
The generator stops, then I wait a short time and put the switch back to auto.
Everything is OK.
Now I am thinking the small board in the transfer panel is bad.
Not thinking, I button everything up and leave.
On my way home I re think what I experienced.
Maybe, just maybe I did not allow enough time for the generator control board to time out in the Transfer Switch.
That is bugging me and I will have to return and give the generator more time to stop before I order the small board in the Transfer switch.
So, I wasted another day and need to return.
 

·
Registered
Joined
·
426 Posts
...Maybe, just maybe I did not allow enough time for the generator control board to time out in the Transfer Switch.
Yes, on page 9 of the manual, you would see:

Testing the Automatic Transfer Switch

Turn the 50 Amp utility disconnect circuit breaker in the main distribution panel to the “OFF” position. The automatic sequence will follow. To go back to utility power, turn the 50 Amp utility disconnect circuit breaker “ON”.

Automatic Sequence

Utility Fail Utility voltage sensor senses when utility voltage is below 70% of nominal. Engine start sequence is initiated after 6 second time delay.
Engine Warm-Up Time delay to allow for engine warm-up before transfer. Use jumper on control board to select delay of 20 seconds or 50 seconds.
Transfer Transfer from utility to generator supply occurs after generator voltage is above set levels. Minimum engine run time is 5 minutes after transfer.
Utility Pickup Voltage pickup level is 80 percent of nominal voltage.
Retransfer Retransfer from generator to utility power is approximately 10 seconds after utility voltage supply is above pickup level and minimum run time is completed.
Engine Cool Down Engine will run for 60 seconds after retransfer.

So, the generator must run for at least 5 minutes AFTER the initial Transfer occurs, the Retransfer occurs 10 seconds AFTER the utility power is determined to be at +80% of nominal (which can take a while) and the above 5 minutes has elapsed, and then the generator will continue to run for at least a minute.

If Retransfer does not occur within 10 minutes, I would suspect the Utility Voltage Sensor.
 

·
Registered
Joined
·
93 Posts
Discussion Starter #10
Tabora, I was curious just how the control board in the transfer switch worked with the relays. Along with you input here is what I found.
Taking the schematic you showed me I set everything at zero.
With no power at either input N1 N2 E1 E2, and F1 & F2.
There can be no power in the transfer panel for this exercise to work.
Start:
When F1 & F2 are at zero which causes the 35 vac transformer in the generator is at zero.
Without 35 vac at pins 15 & 16 the board sends 12 vdc to energize the start solenoid and the gas valve.
The generator starts.
240 vac is applied to pins 16 & 17 on the generator board and the six second time is in place.
This signal tells the generator board that the generator is running and the start relay drops out.
At this time 240 vac is sent to E1 & E2. and to the J1 & J2 terminals of the control board in the transfer switch panel.
One more thing needs to happen before the E relay can pick up.
J7 must be supplied with the other half of the 240 vac to allow E to pick up and this is where the 30 to 50 seconds comes in.
Once J7 is timed out as you said the breakers are supplied with the 240 vac from the generator and everything is on power from the generator.
Shut down...
Upon Utility being coming back on line, a similar event must happen as N1 & N2 plus J3 & J4 are at 240 vac.
Time is involved as you said, J7 must time out first to energize N1.
At some point J5 puts 240 vac on F2 which sends 34 vac to the generator board pins 14 & 15 which disables the generator board beginning the start sequence.
Where I missed the mark is that i did not know that the generator must run 5 minutes after start along with the other times involved.
Looks like this has been lesson 101 for the Briggs for which I sincerely appreciate your help.
I bet the generator is fixed, I just need to allow it to go thru the times.
 

·
Registered
Joined
·
139 Posts
I have run into issues where residual magnetism prevented a relay from releasing after being held operated.

But it sounds like you found your problem to be a cool-down timer function.
 

·
Registered
Joined
·
93 Posts
Discussion Starter #12
Well a return visit to let the generator run it's time and here is the results:
15 seconds until start after the utility was removed and the generator started and applied power.
I let it run for a few minutes and then reset the utility breaker.
4 minutes later the relays switched restoring utility power to the breakers.
A wait of 2 minutes and the generator shut down.
I had a big smile knowing it is fixed.
 

·
Registered
Joined
·
139 Posts
Those timing functions are called (in the order you present): Start Delay; Hold Over; Cool Down.
 
1 - 13 of 13 Posts
Top