Cummins/Onan — Checking reactors A and B (Step 2)
Testing & diagnosis · Magneciter reactors
From a Cummins/Onan service manual covering: 10.0JC, 12.5JC, 15.0JC, 4.0JB, 5.0JB, 6.0JB, 6.1JB, 7.5JB, 7.6JB. Check it applies to your exact model before use.
Applies to: Cummins/Onan 10.0JC, Cummins/Onan 12.5JC, Cummins/Onan 15.0JC, Cummins/Onan 5.0JB, Cummins/Onan 6.0JB, Cummins/Onan 6.1JB, Cummins/Onan 7.5JB, Cummins/Onan 7.6JB, Cummins/Onan JB engine, Cummins/Onan JC engine
Before you start
- Resistance readings between G1 and G2 cannot be read with accuracy on the multimeter
Procedure
- Isolate one gate winding by disconnecting either end of gate winding G1-G2; measure resistance across G1-G2
- Isolate one control winding by disconnecting either lead C1 or C2; measure resistance across C1-C2
- Connect one meter lead to the disconnected gate winding lead and the other to the disconnected control winding lead; check for continuity
- Reactor is serviceable if resistance is within 20 percent of the listed value and there is no continuity between control and gate windings
- Reactor is defective if there is an open circuit in either winding or continuity between the windings; replace it
Tools required
- accurate ohmmeter Amazon
Tool links are Amazon searches (affiliate links); manufacturer special tools may only be available from a dealer.
Specs & values
- Refer to Table 5
Full service-parts list: Cummins/Onan 10.0JC →, Cummins/Onan 12.5JC →, Cummins/Onan 15.0JC →, Cummins/Onan 5.0JB →, Cummins/Onan 6.0JB →, Cummins/Onan 6.1JB →, Cummins/Onan 7.5JB →, Cummins/Onan 7.6JB →
Source: Cummins/Onan service manual. Steps and values are as documented; always cross-check against the official manual and any later revisions for your exact serial number before servicing.