Cummins 20KW Generator low voltage wiring

[roger]

The Cummins generator is far superior to the Generac’s, but their wiring diagrams are the worst.

I agree and I suggest Cummins to people asking my opinion. But besides the wiring diagrams being sub par their whole installation and owners manual falls into that category

 

[MGRABHAM]

I went back and wired it per the customer wiring diagram.
ATS TB4-1 to GenSet TB1-1
ATS TB4-2 to GenSet TB1-2
ATS TB4-3 to GenSet TB1-3
ATS TB4-4 to GenSet TB1-4
ATS TB4-5 to GenSet TB1-5
ATS TB4-6 to GenSet TB1-6
ATS TB4-7 to GenSet TB1-7
ATS TB4-8 to GenSet TB1-8
ATS TB4-9 to GenSet TB1-9

Only a manual start works and it will switched the load from grid to the generator when i turn the utility power on or off it does not sense this change. When I turn the generator off it switch back to utility power. So the unit is not working in the auto mode when grid power if off or on with this configuration.

 

[MGRABHAM]

Went back and wired it per the customer wiring attachment. All ATS T4-1 thru 9 straight thru to the GenSet TB1-1 thru TB1- 9 matching number sequence. The generator is not auto sensing the grid power if its on or off is not working. However if I fire up the generator manually it will switch the load from grid to generator, when I turn grid power back on the generator keeps carrying the load until I turn off the generator the it switches back to the utility grid.

 

[Knuckle Dragger]

Well no luck, turned of utility power with genset remote & standby enabled, this config. TB4-1 tied to genset TB6-ATS,
TB-4 tied to genset TB7-gnd with & without jumper to TB-3, TB4-7 tied to genset TB5--TB4-7.

For what it's worth:
My cheat sheet has for the basics:
ATS T-1=Genset TB-6
ATS T-3-4 jumped= Genset TB-7
ATS T-7 =Genset TB-5

 

[MGRABHAM]

Thank you, tried that config. it did not work. Any other suggestions?

 

[MGRABHAM]

I went with this config. from the ats TB4 to the GenSet TB1-1 thru TB1-9. Only works in the manual startup mode, it does switch the grid load to the generator even if grid power is on or off. Manual startup will continue to carry the load until its turn off then it switches back to the grid. The auto sensing of the grid is not working to start the generator automatically or to turn it off if the grid power is restored.

 

[hillbilly1]

Sounds like the transfer output on the generator is being energized when it is running. (K1 is being energized) K2 should be powered from the utility source, when it is de-energized, the contact closes, telling the generator to start, once the generator is up to speed, and any time delay built in expires, it energizes K1, transferring to generator power, once K2 is re-energized, the timer in the generator starts the countdown to re-transfer. Do the voltage check on 1 and 4 that I mentioned in a previous post.

 

[MGRABHAM]

Okay, just to be clear I need to measure the voltage between TB4-1and TB4-4 it should be 12v with grid power on.

 

[hillbilly1]

Yes

 

[hillbilly1]

With utility off, it should go to zero. If it stays at 12 volts, the voltage sense relay is bad.

 

[MGRABHAM]

What's your take on the customer wiring configuration above?

 

[hillbilly1]

What's your take on the customer wiring configuration above?

I think a lot of the connections are for a remote annunciation, switch position is not needed for the generator to operate.

 

[hillbilly1]

Looked at your label again, I think I see the problem, they have the ats control on three instead of seven unlike on the newer switches, so the wire that normally goes to seven in the ATS, goes to three, no jumper between three and four. Seven will get the wire marked B+ from the generator, four will get the wire marked B- from the generator. That should fix your problem. One remains as is to utility sense at the generator (remote start)

 

[LarryFine]

Only a manual start works and it will switched the load from grid to the generator when i turn the utility power on or off it does not sense this change. When I turn the generator off it switch back to utility power. So the unit is not working in the auto mode when grid power if off or on with this configuration.

It almost sounds like the utility and generator feeds are reversed, and the ATS is sensing the generator as if it was the utility.

 

[MGRABHAM]

Looked at your label again, I think I see the problem, they have the ats control on three instead of seven unlike on the newer switches, so the wire that normally goes to seven in the ATS, goes to three, no jumper between three and four. Seven will get the wire marked B+ from the generator, four will get the wire marked B- from the generator. That should fix your problem. One remains as is to utility sense at the generator (remote start)

Please help verify the following changes.

ATS TB4-1 Utility Sense tied to GenSet TB1-1 labeled "load control"

ATS TB4-3 Trans Switch tied to GenSet TB1-6 Labeled "ATS TB4-1"

ATS TB4-4 B- tied to GenSet TB1-7 Labeled "GND - ATS TB4-5"

ATS TB4-7 B+ tied to GenSet TB1-8 Labeled "Fused B+"

 

[hillbilly1]

Please help verify the following changes.

ATS TB4-1 Utility Sense tied to GenSet TB1-1 labeled "load control"

ATS TB4-3 Trans Switch tied to GenSet TB1-6 Labeled "ATS TB4-1"

ATS TB4-4 B- tied to GenSet TB1-7 Labeled "GND - ATS TB4-5"

ATS TB4-7 B+ tied to GenSet TB1-8 Labeled "Fused B+"

You need to swap TB4-1 and TB4-3. According to that label, TB1-1 is the transfer signal, and TB1-6 is start signal.

 

[MGRABHAM]

Okay, got it. I will give this config. a try this evening. Thank you, fingers crossed.

 

[synchro]

Please help verify the following changes.

ATS TB4-1 Utility Sense tied to GenSet TB1-1 labeled "load control"

ATS TB4-3 Trans Switch tied to GenSet TB1-6 Labeled "ATS TB4-1"

ATS TB4-4 B- tied to GenSet TB1-7 Labeled "GND - ATS TB4-5"

ATS TB4-7 B+ tied to GenSet TB1-8 Labeled "Fused B+"

You need to swap TB4-1 and TB4-3. According to that label, TB1-1 is the transfer signal, and TB1-6 is start signal.

If the generator terminals are like in the diagram below, it seems that generator TB1-5 is for ATS control and not TB1-1. If so, I think TB1-5 should be tied to TB4-3 of the ATS.

 

[MGRABHAM]

Yes it matches the table illustrated above therefore I will tie the ATS TB4-3 to the GenSet TB1-5. The label on TB1-5 reads "TB-5 TB4-7 (RAxxx) or TB4-5 RA112L1)

 

[MGRABHAM]

See the attachment.