The Cummins/Onan JC is a air cooled engine rated at 1800 rpm. It powers generator sets from Cummins/Onan, including the 10.0JC, 12.5JC and 15.0JC.
Also known as: Onan JC
| Aspiration | Air cooled |
|---|---|
| Rated speed | 1800 rpm |
How to read your Cummins/Onan engine serial & model number →
| Symptom | Cause | Remedy |
|---|---|---|
| Generator Set Does Not Stop When Switch Is Pushed To Stop | 1a. Defective Start / Stop / Test switch (S11).<br>1b. Defective relay (K14). | 1 a. Test Start / Stop / Test switch and wiring.<br>1 b. Test relay K14 and wiring. |
| No AC Output Voltage | 1. The line circuit breaker is OFF.<br>2. The line circuit breaker has TRIPPED.<br>3. The line circuit breaker is faulty.<br>4. Reid circuit breaker CB21 has TRIPPED. | 1. Rnd out why the circuit breaker was turned OFF, make sure it is safe to reconnect power, and then throw the circuit breaker ON.<br>2. Shut down the set and service as necessary to dear the short drcuit or ground fault that caused tripping, and then RESET the drcuit breaker and start the set.<br>3. Shut down the set, make sure the power output lines from the set have been disconnected from all other sources of power, attempt to RESET the drcuit breaker and throw it ON and check for electrical continuity across each line contact. Replace the drcuit breaker if there is measurable resistance across any contact.<br>4. RESET the drcuit breaker. If it keeps tripping, troubleshoot according to Trouble heading. |
| Field Circuit Breaker Keeps Tripping | 5. Field circuit breaker CB21 is faulty.<br>6. The field has lost its residual magnetism.<br>7. The generator is faulty. | 5. Shut down the set, attempt to RESET the drcuit breaker and disconnect either lead. Replace the drcuit breaker if there is measurable resistance across the terminals.<br>6. If reference voltage across TB21-1 & 2 is not 20VAC or more, flash the field according to Servicing the Generator in Section 5.<br>7. Disconnect stator leads 1 & 2 from TB21 -1 & 2. Reference voltage across leads must be 20 VAC or more. If not, troubleshoot according to Trouble heading, Field Circuit Breaker Keeps Tripping. |
| Output Voltage Is Too High Or Too Low | 1. Engine speed is too high or too low.<br>2. The voltage has been adjusted improperly.<br>3. Improper connections have been made at the generator output terminals.<br>4. The rotating rectifier assembly (diodes CR1 through CR6) is faulty.<br>5. Defective reference transformer T21.<br>6. Voltage Regulator VR21 is faulty. | 1 a. Adjust engine speed according to engine service manual.<br>1b. If engine speed is unstable, troubleshoot according to Table 4-2, Control Troubleshooting - Run Mode.<br>2. Adjust output voltage according to AC Control in Section 2.<br>3. Shut down the set and reconnect according to the appropriate reconnection diagram (Page 7-7).<br>4. Shut down the set and check each diode according to Servicing the Generator in Section 5. Service as necessary.<br>5. Shut down the set and check T21 winding resistances according to Servicing the Generator in Section 5.<br>6. Replace the voltage regulator. |
| Engine Does Not Crank. | 1. Fuse FI on the control panel is blown. 2. Insufficient battery voltage due to: a. Batteries not charged. b. Battery connections loose or dirty. c. Insufficient battery charging voltage. 3. Start solenoid (K11) not energized due to: a. Defective Start / Stop / Test switch (S11). b. Defective solenoid (K11). 4. Starter (B1) not energized due to: a. Open circuit between battery (B+) and start solenoid (BAT). b. Defective starter (B1). | 1. Replace the fuse with one of the same type and amp rating. If fuse FI blows again, refer to wiring diagram in Section 7 to locate short or defective component. 2a. Recharge or replace the battery. Specific gravity for a fully charged battery is approximately 1.260 at 80° F (27° C). 2b. Clean and tighten or replace the battery cable connectors and cables at the battery and the set. 2c. Adjust charge rate of battery charging circuit. Refer to Battery Charge Rate Adjustment in Section 6. 3a. Test Start / Stop / Test switch and wiring. 3b. Test solenoid K11 and wiring. 4a. Check wiring continuity between battery (B+) and the start solenoid contact (BAT). 4b. Test starter, see engine service manual. |
| Engine Cranks But Does Not Start. | 1. Restricted fuel supply due to: a. Closed shutoff valve in supply line. b. Engine is not getting fuel. 2. The engine ignition system is malfunctioning (ignition coil, distributor, spark plugs, high tension spark plug and coil cables and timing). 3. Run relay (K12) not energized due to: a. Defective start solenoid (K11). b. Defective run relay (K12). 4. Optional fuel solenoid (K1) not energized due to: a. Open in fuel solenoid circuit. b. Defective fuel solenoid. 5. Optional fuel tank solenoid (K2) not energized due to: a. Open in fuel tank solenoid circuit. b. Defective fuel tank solenoid. | 1a. Open any closed shutoff valve in the fuel line supplying the engine. 1b. Fill the main fuel supply tank if the set is gasoline or propane fueled, for natural gas fueled sets, check with the gas utility. 2. Service according to the engine service manual. 3a. Test solenoid K11 and wiring. 3b. Test run relay K12 and wiring. 4a. Check wiring continuity of fuel solenoid circuit. 4b. Test fuel solenoid. 5a. Check wiring continuity of fuel tank solenoid circuit. 5b. Test fuel tank solenoid. |
| Cranking Voltage Is Too Low To Reach Required Cranking Speed. | While cranking the engine, measure voltage directly across the battery terminals and then immediately across the starter motor terminal and the grounding bolt on the block. Cable, terminal or relay contact resistance is too high if the difference is more than 1 volt. Service as necessary. Recharge or replace the battery. Specific gravity for a fully charged battery is approximately 1.260 at 80° F (27° C). | |
| Fuel Pump Is Malfunctioning. | The fuel pump (gasoline-fueled sets) is malfunctioning. | Replace or service the fuel pump according to the engine service manual. |
| Carburetor Fuel Passages Are Clogged Or The Choke Needs Adjustment (Gasoline-Fueled Sets). | The carburetor fuel passages are clogged or the choke needs adjustment (gasoline-fueled sets). | Clean and rebuild gasoline carburetors with the appropriate carburetor kit according to the kit instructions. Adjust fuel mixture according to the engine service manual. Refer to Section 6, Adjustments, to service the automatic choke. |
| Engine Starts, but Stops When Start Switch is Released | 1. Centrifugal switch (SI) faulty or out of adjustment. 2. Defective fault sensor switch (low oil pressure, high air temp., or overspeed switch). 3. Open or defective fault circuit breaker (CB4, CB5, or CB6). 4. Diode CR12 defective. | 1. Refer to Section 6, Adjustments. 2. Refer to engine service manual. 3. Check breakers. If open, locate and correct cause of fault. 4. A good diode has a higher reading in one direction than the other, if both readings are high, or low, diode is defective. |
| Engine Starts, but Lacks Power or Stops | 1. Fuel delivery to the set is inadequate. 2. Fuel is contaminated. 3. Dirty air filter. 4. The governor and carburetor fuel mixture adjustments are incorrect. 5. Gaseous fuel delivery (vapor withdrawal) to the set is inadequate. | 1 a. Check for and replace clogged fuel lines and filters. 1 b. Measure the vertical distance between the fuel lift pump on the engine and the bottom of the dip tube in the supply tank. Make necessary provisions so that lift does not exceed 6 feet (1.8 metres). 2. Connect the set to a container of fuel of known quality and run the set under various loads. Replace the contents of the fuel supply tank if there is a noticeable improvement in performance. 3. Check air filter and dean if dirty. 4. Adjust the carburetor fuel mixture according to the engine service manual. Refer to Section 6, Adjustments, to service the automatic choke. 5. Check the gas supply pressure at the fuel inlet fitting on the skid. Make necessary provisions so that gas supply pressure is at least 10 inches (254 mm) Water Column (WC) when the set is under full load, and not more than 20 inches (508 mm) WC. |
| Fault Shutdown Occurs, but No Fault Lamp Indication | Perform lamp test by engaging Alarm Test switch. All lamps should light. Replace defective lamp. | |
| Fault Lamp Illuminated: a. Overspeed b. Low Oil Pressure c. High Engine Temperature | A. Refer to Section 6, Adjustments, to verify operation of overspeed switch (S5). b. Check oil level and add oil if low. Monitor oil pressure gauge. If gauge reading is within normal range, switch S4 is defective. If oil pressure is low, stop engine immediately. Refer to engine service manual. c. Check air inlet to make sure it is open and free of debris. Refer to engine service manual to verify operation of high engine temp switch (S6). | |
| No Fault Condition | Check condition of all control wiring to ensure correct and secure terminal connections. | |
| Low Battery Voltage | 1. Weak or discharged battery due to: a. Low charge rate. b. Low electrolyte level in battery. c. Long periods of non-use. d. Improperly wired battery. | 1 a. Adjust slide tap on adjustable resistor R21 for proper charge rate. Refer to Battery Charge Rate Adjustment in Section 6. 1 b. Replenish electrolyte and recharge battery. 1 c. Connect a separate battery charger to bring battery up to full charge. 1 d. Reconnect and check battery connection. |
| Generator Set Charging Circuit Not Functioning | 2a. Open in circuit between generator B1-B2 winding and battery (B+). 2b. Open charging resistor (R21). 2c. Diode CR21 defective. 2d. Generator B1-B2 defective. | Check all wiring connections between the generator B1-B2 windings and the battery B+ connections, including all connections to the diode CR21 and battery charge resistor (R1). Remove wires from the charge resistor (R21) and measure its resistance. A normal reading |
| The engine will not crank. | Possible fault with control or starting system. | Check for the following conditions: a. Fuse F1 has blown. Replace the fuse with one of the same type and amp rating. b. Fault circuit breaker has tripped. Service the fault, and reset the circuit breaker. c. Poor battery cable connections. Clean the battery |
| Indicates insufficient battery voltage | Batteries not charged. Battery connections loose or dirty. Insufficient battery charging voltage (contact an Onan distributor for assistance). | Contact an Onan distributor for assistance. |
| The engine cranks, but does not start or starts and then shuts down. | Check for empty fuel tank, fuel leaks, or plugged fuel lines and correct as required. Check for dirty fuel filter and replace if necessary (see Maintenance section). Check for dirty or plugged air filter and replace if necessary (see Maintenance section). Check ignition system (see Maintenance section). Contact an Onan distributor for assistance if none of the above. | |
| Engine runs and then shuts down | Engine has exceeded normal operating speed. | Contact an Onan distributor for service. |
| Fault lamp lights but no fault exists. Engine gauges show oil pressure. | Engine sensor is faulty. Contact an Onan distributor for assistance. | |
| Fault lamp(s) does not light | Replace defective lamp(s). | |
| No AC output voltage because the line circuit breaker (if provided) or the field circuit breaker has tripped. | Determine the cause (overload or short circuit) and clear the fault. Reset the line circuit breaker and/or the field circuit breaker. Contact an Onan distributor if voltage buildup causes breaker to trip. |
Fault codes and symptom→remedy steps extracted from this engine’s service/owner documentation; verify against the official manual before servicing.
Compiled from service & troubleshooting documentation across every generator set that uses the Cummins/Onan JC.
Step-by-step procedures compiled from the Cummins/Onan service manual for this engine.
| Item | Action | Hours | Months | Notes |
|---|---|---|---|---|
| Exhaust system | Inspect | 8 hr | Daily | |
| Fuel supply | Check | 8 hr | ||
| Generator set | Inspect | 8 hr | Daily | |
| Inspect plant generally | Inspect | 8 hr | Periodic Service Guide | |
| Oil level | Check | 8 hr | ||
| Air cleaner | Check | 50 hr | ||
| Battery | Check | 50 hr | Check condition of the battery | |
| Crankcase oil | Change | 100 hr | First service — Change crankcase oil after the first 50 hours | |
| Cylinder head bolts | Adjust | 50 hr | First service — After the first 50 hours of operation, retighten the cylinder head bolts | |
| Cylinder head bolts and valve clearance | Adjust | 50 hr | First service — After first 50 hours on a new or overhauled engine | |
| Air cleaner | Other | 100 hr | Service more often under extreme dust conditions | |
| Air cleaner (dry paper cartridge) | Clean | 100 hr | Do not wash; replace at least every 500 hours | |
| Battery water level and charge condition | Check | 100 hr | ||
| Fuel filter | Clean | 100 hr | Fuel filter sediment bowl | |
| Governor linkage | Check | 100 hr | ||
| Governor linkage | Clean | 100 hr | Clean and adjust (governor rod ball joints) | |
| Air cleaner (foam element) | Clean | 200 hr | Replace only if damaged | |
| Battery electrolyte level | Check | 200 hr | ||
| Breaker points | Check | 200 hr | ||
| Crankcase breather | Clean | 200 hr | ||
| Crankcase breather | Replace | 200 hr | Series JB | |
| Fuel sediment bowl | Drain | 200 hr | Empty fuel sediment bowl | |
| Generator | Clean | 1000 hr | Clean the generator | |
| Ignition breaker points | Adjust | 200 hr | Series JC; clean and adjust | |
| Oil filter | Replace | 200 hr | Normally every 200 hours; shorten if oil very dirty | |
| Spark plug | Check | 200 hr | Check the spark plug gap | |
| Breather baffle | Clean | 500 hr | ||
| Build-up relay (02SX exciters) | Clean | 500 hr | 02SX exciters require build-up relay cleaning | |
| Generator brushes | Inspect | 500 hr | ||
| PCV valve | Clean | 500 hr | Series JC | |
| PCV valve (JC begin Spec T) | Clean | 500 hr | Wash in diesel fuel or kerosene | |
| Starter disconnect breaker | Replace | 500 hr | Service the starter disconnect breaker | |
| Valve clearance | Check | 500 hr | First service — Tighten head bolts and adjust valve clearance after first 50 hours on a new or overhauled engine | |
| Voltage build-up relay (02SX exciters) | Clean | 500 hr | J-series generator sets using 02SX exciters | |
| Ball bearing | Inspect | 1000 hr | Inspect every 1000 hours with the plant running | |
| Brushes | Inspect | 1000 hr | Revolving field generator | |
| Collector rings | Inspect | 1000 hr | ||
| Cooling fins (cylinder block and heads) | Clean | 1000 hr | More often under dirty conditions | |
| Exciter | Inspect | 1000 hr | Periodic inspection of the exciter | |
| Exciter, ball-bearing, collector rings, brushes | Inspect | 1000 hr | at least every 1000 hours |
Extracted from the manufacturer documentation linked to this model. Values are copied as printed; confirm against your unit's manual and serial number.
| Type | Item | Value | Unit | Condition |
|---|---|---|---|---|
| Clearance | Armature runout | less than .002 | in. | |
| Clearance | Brush wear limit | 5/16 | inch | replace when worn to this |
| Clearance | Cam Tappet Diameter (Begin Spec P) | .8725 - .8730 | in | |
| Clearance | Cam Tappet Diameter (Prior to Spec P) | .7475 - .7480 | in | |
| Clearance | Cam Tappet Hole Diameter (Begin Spec P) | .8755 - .8765 | in | |
| Clearance | Cam Tappet Hole Diameter (Prior to Spec P) | .7505 - .7515 | in | |
| Clearance | Camshaft Bearing Clearance Limit | .0012 - .0037 | in | |
| Clearance | Camshaft End Play | .007 - .039 | in | |
| Clearance | Camshaft to bearing clearance | .0012 to .0037 | in. | |
| Clearance | Collector rings T.I.R. | .002 | inch | |
| Clearance | Collector rings Total Indicated Reading (T.I.R.) | .002 | in. | |
| Clearance | Connecting Rod Bearing-to-Crankshaft Clearance | .001 - .003 | in | |
| Clearance | Connecting Rod Bushing Clearance | .0002 - .0007 | in | |
| Clearance | Connecting Rod Journal Diameter | 2.0600 - 2.0605 | in | |
| Clearance | Connecting Rod Large Bore Diameter | 2.1871 - 2.1876 | in | |
| Clearance | Connecting Rod Small Bore Diameter | 1.044 - 1.045 | in | |
| Clearance | Connecting rod bearing to crankshaft journal clearance | .001 to .003 | in. | |
| Clearance | Connecting rod upper bushing to piston pin clearance | .0002 to .0007 | in. | |
| Clearance | Crankshaft End Play | .010 - .015 | in | |
| Clearance | Crankshaft Main Bearing Journal Diameter | 2.2430 - 2.2435 | in | |
| Clearance | Crankshaft Main Bearing Journal Diameter | 2.2440 - 2.2445 | in | |
| Clearance | Crankshaft end play | .010 to .015 | in. | |
| Clearance | Crosshead to valve spring retainer | .025 | inch | minimum |
| Clearance | Cylinder Bore | 3.250 | in | |
| Clearance | Distributor shaft side play | less than .005 | in | 5 lb pull |
| Clearance | Exhaust Valve Guide Clearance | .0030 - .0050 | in | |
| Clearance | Fuel pump coupling buffer end clearance | 1/16 | inch | minimum |
| Clearance | Fuel pump drive coupling alignment | .010 | inch | at 4 equidistant points on pump spider |
| Clearance | Intake Valve Guide Clearance | .001 - .003 | in | |
| Clearance | Intake Valve Stem Diameter | .3405 - .3415 | in | |
| Clearance | Main Bearing Clearance | .0014 - .0052 | in | |
| Clearance | Main Bearing Clearance | .0024 - .0052 | in | |
| Clearance | Piston Clearance to Cylinder Wall (90 deg to pin, just below oil ring groove) | .0012 - .0032 | in | |
| Clearance | Piston Pin | Thumb Push Fit | ||
| Clearance | Piston Ring Width, 2nd | .0925 - .0935 | in | |
| Clearance | Piston Ring Width, 3rd | .1860 - .1865 | in | |
| Clearance | Piston Ring Width, Top | .0925 - .0935 | in | |
| Clearance | Piston clearance (90 deg from piston pin axis, 3/8 in. below oil control ring) | .0012 - .0032 | in. | |
| Clearance | Starter armature end play | .005 - .030 | in | |
| Clearance | Starter pinion clearance | .09 +/- .02 | in | target .07 |
| Gap | Belt deflection | equal to thickness of belt for each foot of free span | approx 13 pounds index finger force | |
| Gap | Breaker Point Gap | .020 | in | |
| Gap | Centrifugal switch contact gap | .020 | in. | |
| Gap | Centrifugal switch point gap | 0.040 | inches | |
| Gap | Distributor breaker point gap | .018 - .022 | in | maximum gap |
| Gap | Ignition breaker point gap | .020 | in | JB |
| Gap | Ignition breaker point gap | 0.018-0.022 | in (0.46-0.58 mm) | |
| Gap | Ignition breaker point gap | 0.019-0.021 | in (0.48-0.53 mm) | |
| Gap | Magneto Pole Shoe Gap | .020 | in | |
| Gap | Magneto pole shoe gap | .025 | in | |
| Gap | Piston Ring Gap | .010 - .020 | in | |
| Gap | Piston ring end gap | .010 to .020 | in. | |
| Gap | Spark Plug Gap | .025 | in | |
| Gap | Spark plug gap | 0.025 | in (0.64 mm) | |
| Gap | Spark plug gap | 0.035 | in (0.89 mm) | |
| Gap | Start-disconnect breaker point gap | .020 | in | |
| Gap | Starter disconnect breaker point gap | 0.020 | in (0.51 mm) | |
| Other | Battery specific gravity when 75 percent charged | 1.290 to 1.225 | 75 percent charged | |
| Other | Center pin extension from camshaft gear | 25/32 | in. | |
| Other | Compression, standard new engine cranking at about 300 rpm | about 110 | psi |
Extracted from the manufacturer documentation linked to this model. Values are copied as printed; confirm against your unit's manual and serial number.
| Fluid | Grade | Standard | Ambient | Capacity | Notes |
|---|---|---|---|---|---|
| Coolant | Clean water, slightly alkaline | pH value range of 8.5 to 10.5 | 100.0 | Keep chromate concentration between 100 and 150 grains per gallon; water should be free of chlorides, sulphates and acids; summer treatment one ounce chromate compound per two or three gallons of water | |
| Engine oil | SAE 30 | API MS, MS/DG, or MS/DM heavy-duty detergent oil | Recommended for 30 deg F and above | ||
| Engine oil | SAE 50 | Squirt a small amount into the cylinder to check for piston blow-by during the compression test | |||
| Engine oil | SAE 5W | Mil-L-10295 | below 0°C | Use where temperatures are not above 0°F (value copied as printed in °F); may need one grade heavier in heavily loaded applications | |
| Engine oil | SAE 5W-20 | API MS, MS/DG, or MS/DM heavy-duty detergent oil | Recommended for 30 deg F and below | ||
| Engine oil | SAE viscosity grades per ambient temperature chart (10W-30, 10W-40, 20W-40, 20W-50, 30 shown on chart) | API service classification SF or SF/CC; must have passed MS Sequence Tests (or ASTM G-IV Sequence Tests); do not use Service DS oil | 3.5 quarts | Includes 0.5 quarts (0.47 l) for the oil filter. Viscosity chart temperature range shown as -20 to 100 F. | |
| Engine oil | SAE-30W | Mil-L-2104-A and/or British Defense Spec. DEF-2101B; Supplement I; Mil-L-2104-B; Series 3 (Mil-L-45199) | Recommended for normal conditions and where sulphur content of diesel fuel is 0.5% to 1% by weight; SAE 20W Series 3 premium oils not required except unusual conditions | ||
| Engine oil | SAE 10W | -10°C to 30°C | Temperatures consistently between -10°F and 30°F (units copied as printed) | ||
| Engine oil | SAE 20 | 20°C to 90°C | Temperatures consistently between 20°F and 90°F (units copied as printed) | ||
| Fuel | Gasoline/propane/natural gas | High compression pistons are necessary for full rated output on natural gas. | |||
| Fuel | Neutral distillate petroleum oil | Viscosity 2.4 to 5.0 centistokes (34 to 42 Saybolt Universal) @ 100°F; Gravity 30 to 42 degrees A.P.I. at 60°F; Cetane Number 40 minimum; Sulphur not to exceed 1% by weight | Pour point 10°F below lowest expected temperature; bottom sediment and water not to exceed .05% by weight; free from suspended matter | ||
| Fuel | Regular grade gasoline | Premium fuels contain more tetra ethyl lead; change stored fuel each season to keep fresh | |||
| Grease | Multi-purpose industrial grease | ASTM Penetration, Normal Worked 285 to 320; Dropping Point 325°F; Water 1% maximum | Do not mix grades or brands; excessive lubrication is as harmful as inadequate lubrication | ||
| Other | Lubricating graphite or light non-gumming oil | For periodic lubrication of governor linkage |
Extracted from the manufacturer documentation linked to this model. Values are copied as printed; confirm against your unit's manual and serial number.
⚠ Injectors must always be adjusted before valves.
⚠ Be careful not to bruise injector tip.
Tools: Inch-pound torque wrench (Snap-On Model TQ12B or equivalent), Screwdriver adapter, Feeler gauge, Wire gauge
⚠ Air housing door must be on when operating engine
Tools: Screwdriver
⚠ Do not force needle valves against seats
Tools: Screwdriver
⚠ Oversensitive adjustment may cause hunting
Tools: Reed frequency meter, Wrench
Tools: Feeler gauge
⚠ Set clearances at room temperature, at least two hours after shutdown
Tools: Feeler gauge, Torque wrench
⚠ Early model four-cylinder engines do not have a BC mark on the flywheel
Tools: feeler gauge
Tools: feeler gauge, torque wrench
⚠ Avoid overcharging.
⚠ Never roll or tighten a belt over the pulley and never pry it on with a tool such as a screwdriver.
⚠ When two or more belts are used, they must be replaced as a set.
⚠ Do not tighten belt beyond figures given to eliminate belt squeak.
⚠ Do not force needle valves against their seats; this will bend the needle.
Tools: Screwdriver (adjusting needles)
⚠ An over-sensitive adjustment may result in a hunting condition.
Tools: Wrench, Reed type frequency meter or mechanical tachometer
Extracted from the manufacturer documentation linked to this model. Values are copied as printed; confirm against your unit's manual and serial number.
| Voltage | Phase | Connection | Leads | Notes |
|---|---|---|---|---|
| 110 | 1 | 518 | V1 | 50 hertz |
| 110/190 | 3 | 53C | V1 | 50 hertz |
| 110/190 | 3 | V1 | 50 Hz; decoded from Figure 3-4 (OCR degraded) | |
| 110/220 | 1 | 518 | V1 | 50 hertz |
| 110/220 | 1 | 53C | V1 | 50 hertz |
| 110/220 | 1 | V1 | 50 Hz; decoded from Figure 3-4 (OCR degraded) | |
| 110/220 | 3 | 518 | V1 | 50 hertz |
| 115 | 1 | 518 | V2 | 50 hertz |
| 115/200 | 3 | 53C | V2 | 50 hertz |
| 115/230 | 1 | 518 | V2 | 50 hertz |
| 115/230 | 1 | 53C | V2 | 50 hertz |
| 115/230 | 1 | V2 | 50 Hz; decoded from Figure 3-4 (OCR degraded) | |
| 115/230 | 3 | 518 | V2 | 50 hertz |
| 118/200 | 3 | V4 | 50 Hz; decoded from Figure 3-4 (OCR degraded) | |
| 120 | 1 | 3C | V1 | 60 hertz |
| 120 | 1 | 518 | V3 | 50 hertz |
| 120 | single | M2-M4 | 12-lead reconnection table | |
| 120, 240 | 1 | 2 wire | Revolving armature; Specs A-S | |
| 120, 240 | single | 2-wire | Revolving armature; Specs A-5 | |
| 120, 240, 120/240 | 1 | Reconnectible for 120, 240 or 120-240 Volts | 4 wire | Revolving armature; Specs A-S |
| 120, 240, 120/240 | 1 | Revolving Field (3R) Reconnectible for 120, 240 or 120-240 Volt | 3 wire | T2 must be grounded if field boost circuit is to work; any other ground may damage the exciter (negative ground only) |
| 120, 240, 120/240 | single | 3R reconnectible | T1, T2, T4, 35 | Revolving field; terminal T2 must be grounded for field boost circuit; negative ground only |
| 120, 240, 120/240 | single | reconnectible | M1, M2, M3, M4 | Revolving armature; Specs A-5 |
| 120-240 | three | delta wound 4-wire (5DR) | Revolving field | |
| 120/208 | 3 | 4 wire | Revolving armature; Specs A-S | |
| 120/208 | 3 | 3C | V1 | 60 hertz |
| 120/208 | 3 | 53C | V3 | 50 hertz |
| 120/208 | 3 | V1 | 60 Hz; decoded from Figure 3-4 (OCR degraded) | |
| 120/208 | three | 4-wire wye | Revolving armature or revolving field; Specs A-5 | |
| 120/208, 277/480, 240/416 | 3 | Revolving Field, Wye Wound, 4-wire, 3-Phase (-4R 120-208, -4XR 277-480, -57XR 240-416) | 4 wire | T1 must be grounded if the field boost circuit is to work (negative ground only) |
Extracted from the manufacturer documentation linked to this model. Values are copied as printed; confirm against your unit's manual and serial number.
The Cummins/Onan JC powers 3 generator set(s), including Cummins/Onan 10.0JC, Cummins/Onan 12.5JC, Cummins/Onan 15.0JC.
A commonly reported issue on generators using the Cummins/Onan JC is: Partial loss of residual in rotor.. Fix: With plant operating, jumper from E2 to heat sink of field rectifier Z until voltage begins to build up. Then remove..