Generac powerpact control issues

[Marcus11]

Iv recently installed a 7.5 powerpact for a customer that has only 120v to the main panel from the utility. I hooked up the generator and automatic transfer switch like i have done in the past. In the main panel there is a jumper allowing 120v on both bus bars. i have, feeding into the transfer switch two conductors that have 120v on them but they are from the same source so its nothing when i go across both of them, but i do get 120v to ground across both legs, when tested individually. When i shut utility power off like im mimicking a power outage the generator starts and transfers the load, the problem is when i restore utility power the generator or the transfer switch doesnt sense that power is restored and just keeps running with the load transfered, i have to manually stop the generator. The fuses are all good and control wireing it triple checked. My question is, if the transfer switch or genset needs to sense 240v to turn off and is the problem that there is only 120v coming in from the utility. Any help would be greatly appreciated, thanks.

 

[ptonsparky]

I would say you're correct.

Why only 120v utility?
Best would be to have it upgraded.

Next, set a customer owned stepup transformer feeding a panel that the generator supplies. Single phase 120 to 240/120.

 

[hillbilly1]

The switching solenoids are 240 volt, so it will not work, and yes, the sense voltage is also 240.

 

[Marcus11]

The switching solenoids are 240 volt, so it will not work, and yes, the sense voltage is also 240.

Thanks for the reply. So there is no way to jump the transfer switch to sense 240v, i read they make a 2 wire start kit, if it would start with 2 wire wouldnt it shut down with 2 wire.

 

[Marcus11]

I would say you're correct.

Why only 120v utility?
Best would be to have it upgraded.

Next, set a customer owned stepup transformer feeding a panel that the generator supplies. Single phase 120 to 240/120.

Thanks for the reply, your saying put in a stepup transformer before the transfer switch.

 

[ptonsparky]

Thanks for the reply, your saying put in a stepup transformer before the transfer switch.

Only if the utility can't be upgraded.

 

[tortuga]

So there is no way to jump the transfer switch to sense 240v

Marcus you can use a control transformer or an auto transformer to boost the 120 to 240 for the sense circuit.

 

[Marcus11]

Marcus you can use a control transformer or an auto transformer to boost the 120 to 240 for the sense circuit.

Thanks for the reply, how would this work? Just a single small step up transformer ran off a separate circuit from the main panel, then tie the secondary 240v of the transformer to the sense circuit?

 

[Joethemechanic]

I haven't seen a 120v service in over 40 years. They were 120v 30 amp if I remember right. That's got to be like 100 years old

 

[Birken Vogt]

The little solenoids take a lot of power to work for a fraction of a second. Make sure your ctrl tx can handle it.

There are 1 or 2 houses around here with 120 volt services also.

 

[tortuga]

I am not sure about the newer controllers but if you study the schematics there is typically a sense circuit N1 and N2 that go from the transfer panel to the controller. That needs to be 240V. You'd need to confirm the controller is just looking for 240 and not 120/240 split phase. As Birken says you'd have to have to size the transformer for the 240V solenoids.

 

[ptonsparky]

I haven't seen a 120v service in over 40 years. They were 120v 30 amp if I remember right. That's got to be like 100 years old

Guessing this is/was summer mountain type cabin at one time.

 

[Marcus11]

I haven't seen a 120v service in over 40 years. They were 120v 30 amp if I remember right. That's got to be like 100 years old

Ya the original cabin was built in 27, so almost 100 years old, although the whole cabin has been rewired in good NM cable, but for some reason never upgraded to 240v.

 

[Marcus11]

The little solenoids take a lot of power to work for a fraction of a second. Make sure your ctrl tx can handle it.

There are 1 or 2 houses around here with 120 volt services also.

I am not sure about the newer controllers but if you study the schematics there is typically a sense circuit N1 and N2 that go from the transfer panel to the controller. That needs to be 240V. You'd need to confirm the controller is just looking for 240 and not 120/240 split phase. As Birken says you'd have to have to size the transformer for the 240V solenoids.

Ya there is a N1 and N2 that go from the transfer to the controller. I havent done too much investigating but if the solenoids sense 240v they would need to be sized for proper current as well? Obviously the step up transformer will step down the current and thats what needs to be sized for the solenoids?

 

[tortuga]

I think as others have suggested your best bet is to see if get them a standard 120/240V split phase service if possible.

 

[hillbilly1]

You may have another problem, I don’t know if they still do, but Generac uses 240 volts for the battery charger too, so you will have to take that into account when sizing the step up transformer.

 

[Marcus11]

I think as others have suggested your best bet is to see if get them a standard 120/240V split phase service if possible.

Ya before starting the project i suggested that the customer would need to upgrade the service and i would not be able to install the generator untill it was upgraded. They insured me that they talked to 2 different people from generac and they said that it wouldn't be a problem, i messed up and took their word and didnt research it. That being said i think an upgrade is the best option. Iv been trying to avoid dealing with the poco there notoriously behind on small stuff like this and can be months out from bringing a new drop down. Its been 10 months waiting for them to approve a small trench for a panel upgrade.

 

[hillbilly1]

Ya before starting the project i suggested that the customer would need to upgrade the service and i would not be able to install the generator untill it was upgraded. They insured me that they talked to 2 different people from generac and they said that it wouldn't be a problem, i messed up and took their word and didnt research it. That being said i think an upgrade is the best option. Iv been trying to avoid dealing with the poco there notoriously behind on small stuff like this and can be months out from bringing a new drop down. Its been 10 months waiting for them to approve a small trench for a panel upgrade.

They probably talked to a Generac salesman, we installed a ton of them many years ago because the original contractor could not handle the huge number of installs. Had more than one customer mad because they told them it would run the whole house. This was before they started using load shed modules.

 

[Marcus11]

They probably talked to a Generac salesman, we installed a ton of them many years ago because the original contractor could not handle the huge number of installs. Had more than one customer mad because they told them it would run the whole house. This was before they started using load shed modules.

Thats exactly what i figured, i asked for the number he called and who he talked to, it was definitely a sales type person, and any technical info they had was from a reading a manual. It was my mistake for not looking into it more. Its strange that the transfer switch isnt sensing there is only 120v coming in, i figured that it may try and start the generator sensing that half of the split phase was out, but it only seems to be sensing the lack of the 240v when the power is restored whitch makes sense also. When things work properly i feel like a wizard, But when things dont and its something seemingly small and a potential easy fix, my head spins and i feel like iv failed my customer.

 

[Marcus11]

They probably talked to a Generac salesman, we installed a ton of them many years ago because the original contractor could not handle the huge number of installs. Had more than one customer mad because they told them it would run the whole house. This was before they started using load shed modules.

Thats exactly what i figured, i asked for the number he called and who he talked to, it was definitely a sales type person, and any technical info they had was from a reading a manual. It was my mistake for not looking into it more. Its strange that the transfer switch isnt sensing there is only 120v coming in, i figured that it may try and start the generator sensing that half of the split phase was out, but it only seems to be sensing the lack of the 240v when the power is restored whitch makes sense also. When things work properly i feel like a wizard, But when things dont and its something seemingly small and a potential easy fix, my head spins and i ferl like iv failed my customer.