Home Forums General Discussion Technical Questions Motor Wiring with Softstart

I put in 2 softstarts on Dover SS Hydros this week. First one was straightforward, across the line, 6 lead, 30hp motor. When I got to the next one, there were only 3 leads in the controller. First I was thinking if it's a 3-wire Wye 30hp motor, I'm going to need a way bigger starter. But when I opened the motor J-box I found it was a 6 lead motor, just wired Delta in the box with 3 leads brought to the controller. What I did was brought all 6 leads back to the starter and wired it like a typical 6 lead motor. My question is, could I have left the wiring like it was and just ran the 3 leads through the starter and fault contractor in series like an in-Line config? This didn't cross my mind until I left but I don't really doubt the motor would work, either way it's wired in delta with L1 to T1&T6, L2 to T2&T4, L3 to T3&T5. Would the Siemens starter have come up with a motor wiring fault? Anyone ever wired one this way? It would have saved me almost 2 hours and a trip to the electrical supply for my boss.

I've done it that way but it draws more current and the starter needs to be larger. I always try to do as you did and re-wire and bring back 6 leads. Takes more time but worth it.

I would second Elevator_Steve. Both S&S and Siemens can be configured to run in-line or wye delta. But you always have to up size the starter 1 or 2 sizes and also make some wiring changes to the soft start. Both brand starters should have ratings for both types of starting on their data tag and in their installation manual.

I will say I have seen a lot of older jobs were the controller has the leads piped across the room to the pump unit and if it is only using 3 leads its certainly a big time saver getting the slightly larger starer and wiring it in-line.

Ya looking at the diagram I see you still need to upsize the starter like it was a 3 lead motor. Unfortunately, you have to go to a way bigger starter. Using Siemens, a 30 hp motor goes from an AF5 to the giant AF14 with the fan. I once had to cram one of those into a little Elevator Electric controller. Tight!

Thanks for the input.

have done it quite a few times dirt, as long as you have the space, it is way easier, and saves time. I think I have at least a dozen or so installed this way in the last 5 years, and not one problem. been using s+s for the last five years, One thing i will say about the s+s, is if you get the smaller units that are for your specific horsepower etc, the lugs are quite small, and when you get to the job you will be fighting the wiring, so much easier to buy the biggest one for a couple hundred extra bucks, and save a headache. plus in my opinion it should last longer.

Thanks I'll keep that in mind. We typically use Siemens but it sure is nice the S & S come in 240 volt.

yes that is important dirt, almost forgot about that. i used to hate the s and s, always wanted the siemens, but once you start using the s and s you will see it is superior as far as installation goes. I have probably installed over 100 s and s starters, and have less then 5 go bad, then ones that have gone bad, unfortunately have gone bad in under a couple of weeks or so. if they make it past a month, they will be in service or many years.