What Could Be Wrong With My Onan Generator?

Onan Generator is a very reliable machine and this article will explain the machine as well how to use it and trouble shooting.

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The problem was engine would certainly start but stop as soon as they begin button was released. (Onan Emerald Green 4kw).

( WEBMASTER REMARK: this information specifies to the model detailed – your particular model may have various specifications as well as wiring links. Consequently, this write-up is meant for general information just. Before doing anything, validate your design number and also specifications).

Likewise, check the oil degree first – There is an oil pressure sensing unit that shuts down the genset if the oil pressure decreases. When the begin button is pressed it bypasses the oil pressure removed circuit, as well as the engine, will run only if the button is pressed in. Inspect the wire to the oil stress sensing unit – the sensor is located under the cover near the oil filter. It might have been ripped off.

It sounds like a couple of things – either you are not obtaining the voltage from the control board to the voltage regulatory authority while cranking (the field flash voltage that develops some initial result from the Genset), or the control panel is giving the voltage but there is an open circuit in the voltage regulatory authority, as well as the field flash voltage isn’t being passed along to the brushes.

To tell which is which, locate the voltage regulator module inside the control box (bolted down at lower left – has a capacitor molded into the top, as well as a brief multi-wire pigtail to a twelve-conductor socket mated to a coordinating twelve-conductor plug in the circuitry harness – J4/P4). Set your voltmeter to dc volts, ground the negative lead, and back-probe pin 7 – you ought to see approx 12v dc here while cranking.

If you do see 12v right here, however, don’t see 10-11 v at the brushes, the control board is good, but the voltage regulatory authority misbehaves. If you don’t see 12v at J4/P4 pin 7 while cranking, make the very same check at P1 (the connector to the control panel) pin5. If you still do not see it here, the control board is bad. * If you see 12v at P1 pin 5 but not at P4 pin 7, the circuitry between them, or the connection at the adapters, is bad.

( For your engineering curved, the voltage comes through a usually open call on K4 that shuts while cranking and a typically closed contact on K2 that opens when there is a result from the genset.) * If you are getting the field flash voltage at P4/pin 7 yet nothing is reaching the brushes, one last check is to check continuity from P4/pin 9 to one brush, and also from P4/pin 10 to the other brush – must be much less than one ohm, and neither need to show any type of connection to ground.

If all this is true, the voltage regulatory authority misbehaves, and also you’ll have to replace it. If you aren’t getting the 12v field flash at P4/pin 7, and also it seems a control board issue, attempt using a jumper lead to briefly use +12 v dc toP4/pin 7 while cranking. If the voltage regulatory authority, brushes, and also armature are OKAY, it must remove and also begin creating outcome – and also continue creating a result as long as it is running.

Sixth sense – based on signs and symptoms and also your gauged 135 ohms comb to clean – is that the voltage regulatory authority is probably bad. The streamlined explanation is the voltage regulator (when the Genset is running) gets excitation voltage from the exciter winding (Q1/Q2) and keeps an eye on the output voltage (L0/L1). It corrects the excitation voltage as well as transforms it to a dc voltage that it passes to the brushes to give an area simply strong sufficient machinery to maintain the wanted outcome voltage.

If there is excessive resistance in the area circuit, the regulator needs to offer a higher area voltage to get enough existing through to give the needed field strength. If taken to extremes, the result tools are switched on 100% trying to offer sufficient area voltage to compel sufficient area current with the resistance to get the outcome voltage where it belongs – and it doesn’t take the tool long to stop working.

If it’s any consolation to you, your new voltage regulator (although under the same part number) is what’s called a ‘capped’ voltage regulatory authority -in this circumstance, it would go to a default minimum voltage out (18v, IIRC) – they transformed to this about spec G or H. * It’s feasible to examine the voltage regulator with a meter that has a great diode check function (note that if it falls short any one of the complying with, it misbehaves – if it passes, it * may * be excellent – or bad – as this is just a static check). *.

Open the control box cover and also disconnect the 12-pin regulatory authority connector. With the meter on ‘diode check’, test in between the following terminal sets, connecting the favorable lead to the initial pin as well as the negative to the 2nd. 5-9, 7-9, 10-9, 11-9, 12-9, 5-10, 5-11, 5-12, 5-3. The voltage regulator is bad if any kind of set shows ‘brief’ or ‘open’ besides set 5-10, which ought to show open. *.

With the regulatory authority still unplugged, you can examine the windings, control panel, etc by leaping 18v dc to pins 9 as well as 10 in the wiring harness plug (which attach to the brushes) while you have the set running – this ought to give you a nominal 120v result, or close enough to switch over the control panel to run mode – after that gauge air conditioning voltage between pins 2 and 3 (should be outcome voltage, 120v +/-), and also determine the exciter winding output between pins 11 and 12 (should have to do with 85% of result voltage).

I usually utilize 2 9v transistor batteries and also a 5 amp fuse to get the 18v. If it switches to run-mode when you do this, and also the output and also exciter voltages look sensible, after that whatever except the voltage regulatory authority is ALRIGHT. Earlier (non-electronic voltage regulatory authority) Onan generators might lose result if the slip rings oxidize, but won’t hurt anything. Later electronic-regulator generators have a ‘capped’ voltage regulatory authority – if the field voltage surpasses what * should * be the maximum for that collection, it journeys a one-shot and goes to the minimal field voltage (normally 18v) – as well as all existing rev substitute regulatory authorities are capped as well as are secured.

If the system is tested by using an 18V supply, is polarity vital?

* It would just be essential if you were doing it with the voltage regulator still connected. Since it won’t be, it doesn’t truly make any distinction (when you obtain a brand-new voltage regulator installed, the field flash will develop – or re-establish – the preferred polarity). As far as the alternator feature itself, the blades have 4 poles – 2 will be N as well as 2 will certainly be S no matter which polarity you hook the 18v up.

As I did not have any kind of idea for how long it was mosting likely to require to obtain the Onan component in I purchased a new reg from Flight Systems.

They are developing their very own design from scratch. Included a 1-year warranty, as well as the reg, is repairable. Their style is a drop-in substitute. The most significant revision that can be seen is the huge cap is physically smaller sized as well as stands upright as well as straight attached to the PCB. Reg included a good 9-page manual that included an area on the concept of operation as well as a block representation. The specification sheet resembles it should have the ability to handle the setting. Procedure = -55 & #deg to 175 & #degF. The exciter specifications are 250V max with 400V peak and 6A constant @ 175 & #deg and also 15A optimal.

Among the features stated was “say goodbye to start-up failures”. Don’t recognize if that is when typ failing takes place however appears to fit the situation when my reg fell short. Trip systems claim they have some control parts that Onan no longer more.

If you need to adj the governor what is the appropriate treatment?

On the speed/frequency problem: initially, take a close look at the genset when it is running with no load – the idle quit screw should NOT be touching, i.e. pressing the throttle lever back against the still quit need to decrease the rate to 55 Hz, and there should show up area in between the screw and also the lever. Change this as needed.

Servicing Onan Generator

February 1, 2017

This auxiliary source of Air Conditioning power requires regular maintenance.

By Mark Quasius, F333630

February 2017

The Recreational Vehicle ready generator, an important component in a motorhome’s electric system, provides 120-volt-AC power (or, relying on the style, 120/240-volt Air Conditioning power) for totally dry outdoor camping or when the teacher is being driven. Onan, a product of Cummins Power Generation, is one of the most preferred trademark names of a Mobile home generator.

This post focuses on the treatments needed to service generators in the Cummins Onan Quiet Diesel (QD) Series, with a concentrate on the maintenance therapies for larger variations (10 kilowatts as well as 12.5 kilowatts). Even within the Cummins Onan product, solution intervals and additionally treatments differ relying on the alternator size along with the day of manufacture; while a few of the fundamentals may put on various other diesel power cell brand names and styles, see to it to examine the proprietor’s guidebook for particular guidelines.

The alternator is housed in a sound-deadening enclosure as well as likewise can be installed to a slide-rail system. This allows the power cell to be prolonged from the front cap for easy get to. Depending upon the year as well as additionally design, a Cummins QSD alternator might be geared up with either an Isuzu or a Kubota water-cooled diesel motor, which are among one of the most counted on the sector. The engine is straight integrated to the generator, unlike belt-driven systems discovered in numerous gasoline-powered generators.

Cummins diesel generators differ from 3.2 kilowatts to 12.5 kilowatts. A four-pole alternator usually needs to be performed at 1,800 rpm to supply 60 hertz of power. However, the smaller dimensions make use of inverter development to allow a variable-speed procedure that raises the engine rpm as the whole lots increase. Larger generators– 10-kilowatt or 12.5-kilowatt– do not make use of inverter innovation; they execute at a constant regulated 1,800 rpm regardless of simply just how much great deals is used.

Treatment Change

The Cummins Onan QD alteratnor has a treatment turn on its space. A second remote switch normally is placed inside the train. Holding the button in the “Run” establishing triggers the brilliance plugs to pre-heat the engine. The button might need to be held a couple of seconds before the engine will certainly crank. This is regular; the moment differs depending upon exactly how cold the ambient temperature is. As quickly as the glow plugs have warmed the engine adequate, the starter involves cranking the engine. As well as also when the engine begins, the switch can be launched. Most of the switches have a red pilot burner that lights up when the generator is running. To stop the generator, hold the button to the “Given up” placement for a little while or more.

If an alternator runs out of gas or its fuel filter is altered, the system won’t begin without first priming the fuel system to hemorrhage out the air. Hold the operation button at the “Stop” setup and also continue holding it. In many cases, you may have the ability to listen to the generator’s electrical gas pump run, yet, no matter, the red pilot light will certainly light up. Launch the treatment switch after 30 secs; the gas system should be keyed. If the generator fails to start, duplicate this procedure. Note that this treatment can be executed at the generator or the remote button in the motorhome.

Diagnostics

Cummins Onan QD generators have considerable diagnostics to spot system errors, which are presented along with brought from the status light on the procedure button. When the light flashes as soon as, then loosens up and likewise duplicates, it shows a closure due to high engine coolant temperature level. If the light flashes two times, rests, in addition to repeats, it shows a reduced oil stress mistake. When the light flashes 3 times, relaxes, and repeats, it shows an option mistake; in that circumstances, a second action is called for to get a certain mistake code.

To bring a solution mistake code, you might initially need to stand up the control by pushing as well as additionally holding the “Stop” switch. After that touch the “Stop” button as soon as. This presents a two-digit option code, which contains 2 collections of flashes. The extremely first collection of flashes stands for the initial range of the code; after a break, the 2nd set of flashes shows the code’s 2nd number. After a prolonged pause, the series repeats. As an example, fault code 36 looks like blink-blink-blink– pause– blink-blink-blink-blink-blink-blink. Press the “Quit” button to stop the flashing code. A total listing of fault codes shows up in the rear of the driver’s guidebook or can be found online in the Cummins Recreational Vehicle alternator Manual.

Requirement Demands

It’s exceptionally vital to exercise a Cummins alternator routinely, due to the truth that generators that relax additional have far more problems. Cummins proprietors manuals define that the power cell needs to be performed at the very least 2 hrs every month if usage is occasional. The generator must be run at around half power to repel moisture from inside the generator, also, to remove oxide from electrical telephone calls as well as also power cell slide rings. Running the gadget at light or no load won’t accomplish that. Exercising the alternator also safeguards your assurance. If a problem establishes in the future as well as likewise the hr meter discloses that the system hasn’t been run much, warranty insurance policy protection might be refuted.

An excellent prestart checklist starts with increasing the alternator slide as well as also getting rid of the side get to cover. After that examine the engine oil degree and also look quickly for anything lost, such as gas or coolant leaks. (Note: On the 6-kilowatt as well as 8-kilowatt Cummins QD generators, the oil is analyzed making use of the dipstick near the stop/start switch.) If you are driving and decide to use the instructor’s air conditioning system, you will not make these checks right afterward, yet do not forget them. Make it part of your normal to examine the generator continually at a camping area, counting on exactly how usually it has been used.

Refer to the generator’s service timetable to see what is required, and also afterward acquire the right filters in addition to liquids. If components require to be purchased, the generator design number in addition to requirements alteration will certainly be needed. This info appears on a placard mounted to the alternator near its breaker and additionally primary procedure switch. The placard, also, suggests the oil capacity of the crankcase along with Cummins Onan component numbers for the most regular filters.

Service Interval

Among one of the most typical option duration is 250 hrs or one year, whichever precedes. It consists of basic engine oil as well as filter modification. Maintenance of gas, as well as air filters, comes at 500 hrs or two-year intervals. However, a brand-new generator calls for oil as well as additionally filter adjustments after 50 human resources to get rid of pollutants from the oil during the engine’s break-in period. Explain the operator’s guidebook for the specific demands of your alternator model.

Engine Oil Along With Filter

To transform the oil and also oil filter, a 7/8-inch socket, as well as ratchet, a drain fry pan, as well as an oil filter wrench, are needed. A set of rubber handwear covers as well as some towels or nonreusable shop towels furthermore been available in beneficial. Cummins generators are understood for having unbelievably limited oil drainpipe lugs when they leave the production center. To chill out the drainpipe plug the very first time, use a huge breaker bar, potentially with a pipe for much more make use of. Various proprietors additionally locate that the manufacturing facility has placed a smaller-diameter oil filter; don’t worry regarding the distinction in measurement between the very first break-in filter and the substitute. However, your oil filter wrench may not fit the smaller filter, so a huge set of channel-lock pliers or a couple of other tools might be required to do away with that filter.

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Begin by warming up the generator engine. Run it long enough to warm up the oil, also, to enabling it to stream using the system. This will guarantee that any type of sort of sludge is liquified along with suspended in the cozy oil. Switch off the engine along with turn off the circuit breaker on the generator. Additionally ensure to disengage the Automatic Generator Begin module, if the motorhome is geared up with one, to make sure that it can not begin the generator throughout service. As soon as everything is set, lengthen the generator and also eliminate the solution access cover from the driver’s side of the generator, if you have not presently.