Starter for 2 Speed Motor - 10 to 20 HP

OK. To save duplication of effort, which suppliers have already been approached without success, then?

no body yet.

Thanks for yor interest

Unless you have a compelling reason to use a two speed starter, you should seriously consider putting a VFD on the high speed windings and using it. VFDs are inexpensive nowadays, and there will be savings in wiring and installation plus benefits of picking any speed you want. If you have to interface to a control system geared to two speeds, most VFDs have the ability to run at two or more pre-set speeds when they receive a contact closure. You can make th two speeds anyting you want.

Can u use a normal starter size1

If you're in a NEMA country, a size 1 is pushing it for a 10 HP motor. I like the guy who says use a VFD. Much more control.

U can use siemens make star delta starter for this.

siemens service as well as quality is very good.

No, you CANNOT use a star-delta starter for a 2 speed motor!

To make sure you get the right kind of motor starter, you need to determine what type of two speed motor it is, 2 speed 1 winding (2S1W) or 2 speed 2 winding (2S2W). The starter is completely different. If it is a 2S1W, then there are two different styles of that, constant torque or constant HP, but given you already know the HP is 1/2 at the slower speed, that means it is a Constant Torque 2S1W or a 2S2W.

Then just go to your favorite control supplier and tell them what you have. If they look at you funny, like they don't understand, then do not buy from them, you will likely get the wrong thing.

By the way, 10HP is NOT pushing it for a NEMA size 1, that is exactly what it is designed for. NEMA sizing is already serious overkill, no need to over size the overkill...

Did not get a specific model to use for constant HP 2 speed motor. VFD,s were considered but ruled out.

motor starters should be capable of Panel mount and not free standing because of space.

Please help.

Size 2 NEMA motor starter is alright thenfor 2 speed motor

need help

Thanks.

But, how speeds will be conrolled by NEMA 2 starter. I have 22500 at one speed and 11000 CFM at 2nd speed.

Did you not read my post? You need to first determine if your motor is 2 speed 1 winding or 2 speed 2 winding before you can select a starter for it. How the starters work is completely different in those two cases.

Can't help you if you don't help yourself...

Sorry.

It is a 2 speed,2 winding motor.

OK. Then a 2S2W starter will consist of 2 separate but mechanically interlocked NEMA size 2, 2-1/2 or 3 motor starters.

So if you buy it from Siemens for US use (assuming so because you used the terms HP and 208V) you can buy that all put together as one unit as follows;

10HP 208V NEMA size 2 = part number 30FUF^32A1V*

15HP 208V NEMA size 2-1/2 = part number 30GUG^32A1V*

20HP 208V NEMA size 3 = part number 30HUG^32A1V*

Where ^ = a code number based on the low speed motor winding FLA (from the nameplate) and * = the coil voltage you need for your control circuit.

These part numbers are for Open style panel mounting starter assemblies. If you need a complete enclosed or combination starter (i.e. with a circuit breaker, control transformer etc.) then it gets more complicated by options.

I also recommend adding a deceleration timer. In the control logic, the timer forces a delay when changing from high to low speed, because you need to allow the motor winding magnetic fields to collapse before you energize the low speed windings, otherwise the motor is a generator until it slows down. For Siemens, that is a suffix A8 at the end of each part number. If you have your own PLC or something else controlling that, you don't need that timer option, but make sure you have about a 2 second delay.

very well said and explained.

During this time I came across Benshaw's MX2 or MX3, also called models RB2 or RB3.

can You sir, or anybody else throw some light on these starters and enlighten us.

Thanks.

Your help is always a pleasure and is appreciated.