Optional Standby Generator- control and power sharing raceway

[hillbilly1]

MD posted a typical installation book (Even with the newer Nexus control system) that is supplied with all Generac RTS type transfer switchs, the wiring diagram (page 9-11) in this PDF is typical of of all Generac RTS ATS wire ups, the only exception is the change of battery charger system and where it is located, when they used to supply the wall wart type (no plug just the lamp cords coming out of it)
At one time the instruction had us installing them in the generator cabinet at the battery, and supplying it with a circuit from the house panel, later they supplied the terminals and a fuse block to connect them in the transfer switch with a tap to one of the load terminals and neutral, they even included the screw and male spade terminal to do this, and the charger output hooked to 194/15B + and 0 - this back fed the battery through these terminals, the 0 terminal is also tied to the cabinet of the generator for a negative grounding of the battery, when they came out with the Nexus controller they built a float charger system right on the main mother board in the generator, so no external charger is needed.

There is a 178 and 183 terminals on some Generac generators, in most cases you will not use them, they are for remote switch automatic starting for use with a manual transfer switch



The electronics is all in the generator, the main controller board is located in the metal box behind where you land your wires, it will have a cover over it, N1 and N2 are an input to this controller and 23 is a -12vdc output to the transfer switch TR relay (ice cube relay) 194/15 is just the positive from the battery that also runs through the 7.5 amp fuse on the generator switch panel, the battery supplies all the power for the controller and the power up to the TR relay, the TR relay switches the set of solenoids that pull the transfer switch one way or the other, these are DC coils fed through a full wave bridge rectifier from the line voltage (240vac), the power to transfer to generator is derived from E-1 and E-2 which is the hots from the generator, this is to keep the transfer switch from transferring to the generator if it is not running or the breaker on it is tripped or off, the transfer to utility coil is fed through the same bridge rectifier but the limit switches will now have it connected to the N1A and N2A which is the utility side of the transfer switch, again if there is no utility power it will not transfer back.

I would presume that the input to the main controller board could be of a high enough impedance that N1 and N2 could pick up some capacitive coupling and if this happens while generator is running it could trigger the system to think that power is restored and transfer back, this could cause it to start cycling back and forth??? that is about the only thing I could see happening, but if it did it could be bad?

That's what's strange about Generac, everybody else has the brains in the transfer switch. Even if there was enough capacitive coupling to fool the controller, there would be a delay in transfer and with the absence of utility would prevent the utility side solenoid from actuating regardless of the dc relay state once it is on generator power. The only possibility would be the generator times out on cool down, and shuts off. That might start the cycle again, but not likely because since the charger comes off the same source as N1 and N2, the impedance should be low.

 

[hurk27]

That's what's strange about Generac, everybody else has the brains in the transfer switch. Even if there was enough capacitive coupling to fool the controller, there would be a delay in transfer and with the absence of utility would prevent the utility side solenoid from actuating regardless of the dc relay state once it is on generator power. The only possibility would be the generator times out on cool down, and shuts off. That might start the cycle again, but not likely because since the charger comes off the same source as N1 and N2, the impedance should be low.

The charger on Generacs came off of E1 (house side) and Neutral, this is because their 3600 rpm air cooled engines on generators 20kw and smaller does not have an alternator, if power is out for any amount of time the generator controls (including the engine controls) are running off the battery because the N1 and N2 is dead, this is why the original chargers that was required to be put in the generator cabinet required a circuit from the house panel, as this would supply the battery charger on utility or generator, how they get power to the charger now is anyones guess as it is built into the Nexus board, I would suspect it is running off the N1 or N2 or both, but if power is out for days that could be a problem if the battery goes dead and they still do not have a alternator on the smaller engines???? the water cooled and super quiet versions 1800 rpm that have industrial engines will have a 30 amp alternator on the engine.

 

[hurk27]

That's what's strange about Generac, everybody else has the brains in the transfer switch. Even if there was enough capacitive coupling to fool the controller, there would be a delay in transfer and with the absence of utility would prevent the utility side solenoid from actuating regardless of the dc relay state once it is on generator power. The only possibility would be the generator times out on cool down, and shuts off. That might start the cycle again, but not likely because since the charger comes off the same source as N1 and N2, the impedance should be low.

The charger on Generacs came off of E1 and N this is because their 3600 rpm air cooled engines on generators 20kw and smaller does not have an alternator, if power is out for any amount of time the generator controls (including the engine controls) are running off the battery because the N1 and N2 is dead, this is why the original chargers that was required to be put in the generator cabinet required a circuit from the house panel, as this would supply the battery charger on utility or generator, how they get power to the charger now is anyones guess as it is built into the Nexus board, I would suspect it is running off the N1 or N2 or both, but if power is out for days that could be a problem if the battery goes dead and they still do not have a alternator on the smaller engines???? the water cooled and super quiet versions 1800 rpm that have industrial engines will have a 30 amp alternator on the engine.

Edited to add since the charger in located now back on the generator, it would be easy for them to pull power from the generator through a small board mounted relay that would switch the charger from N1 to generator L1 as both would be present?

 

[hillbilly1]

The charger on Generacs came off of E1 and N this is because their 3600 rpm air cooled engines on generators 20kw and smaller does not have an alternator, if power is out for any amount of time the generator controls (including the engine controls) are running off the battery because the N1 and N2 is dead, this is why the original chargers that was required to be put in the generator cabinet required a circuit from the house panel, as this would supply the battery charger on utility or generator, how they get power to the charger now is anyones guess as it is built into the Nexus board, I would suspect it is running off the N1 or N2 or both, but if power is out for days that could be a problem if the battery goes dead and they still do not have a alternator on the smaller engines???? the water cooled and super quiet versions 1800 rpm that have industrial engines will have a 30 amp alternator on the engine.

Edited to add since the charger in located now back on the generator, it would be easy for them to pull power from the generator through a small board mounted relay that would switch the charger from N1 to generator L1 as both would be present?

We must be installing a different Generac generator, because all of ours that we installed used a 240 volt charger that came off N1 and N2, if it came off the generator output, then the charger would only work while the generator was running. I've only installed one Nexus controlled generator, and we had to replace it with a Kohler because the Nexus controller was unadjustable for start and transfer times. It took too long to start and transfer to meet fire code in a commercial building.

 

[Dr Mantis Toboggan]

hurk, I found the manual for the ATS alone, it is a bit different than the one MD posted as you already know. Unfortunately, it doesn't have the same exception that his had. In mine it says that you have to use 2 conduits.

Here is a partial screenshot that I used for another thread, you can see it on the left side:

 

[hurk27]

We must be installing a different Generac generator, because all of ours that we installed used a 240 volt charger that came off N1 and N2, if it came off the generator output, then the charger would only work while the generator was running. I've only installed one Nexus controlled generator, and we had to replace it with a Kohler because the Nexus controller was unadjustable for start and transfer times. It took too long to start and transfer to meet fire code in a commercial building.

Are we talking about 20kw air cooled 3600 rmp and smaller? water cooled, quiet (1800rpm) and larger then 20kw will have a 30 amp altenator on the engine as these are not air cooled engines? if the engine has an altenator then N1 and N2 will be fine to charge the unit in stand by, but like I said, before the Nexus controller came out the charger had to be wired to the load side of the transfer switch or the battery would not be charged when the generator was running on an outage as N1 and N2 would be dead and the air cooled engines do not have an altenator.
Also the battery charger I got was a 120-240 volt switching float charger, the instruction I had said to wire it up to E-1 and the Neutral bar in the transfer switch, this was the first one I did that had the float charger and had a 120-240 volt input, the older ones were 120 volt trickle chargers that were burning the water out of the batteries causing them to explode, these older ones mounted in the generator housing and had a 120 volt feed from the house panel.

hurk, I found the manual for the ATS alone, it is a bit different than the one MD posted as you already know. Unfortunately, it doesn't have the same exception that his had. In mine it says that you have to use 2 conduits.

Here is a partial screenshot that I used for another thread, you can see it on the left side:

Dr that is a load sheding transfer switch as it has an electronic board in it, it might have had more problems with the LV wires in the same conduit??? just not sure, we use the RTS "W" series ATS's and these instructions had the 30' exception.