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12-14-2011, 11:23 AM #1
Strange 220/440 motor wiring diagram (photo)
This, on aprox 5 hp motor of Taiwanese radial drill. Never seen wire arrangement diagram like this....can any of you figure it out ?
12-14-2011, 11:33 AM #2
Makes perfect sense to me.
Parallel for low voltage, series for high voltage, whether Y or ∆.
But, using Y starting and ∆ running.
12-14-2011, 11:44 AM #3
I bet if you connect it as shown on the plate, the motor will run just fine.
If you don't have a starter switch, just hook it up in the run configuration at the correct voltage.
12-14-2011, 12:37 PM #4
This is exactly the 12 wire config. I am dealing with my "20 HP RPC stalling post".
12-14-2011, 12:53 PM #5
12-14-2011, 02:24 PM #6
12 leads is actualy typical, its just that usuale three are tucked into the motor and never change, so you dont think about them.
The interesting part is going to be the switch gear to go between Delta and Y.
In low voltage, either configuration is set up with the following pairs
R - 7&1
S - 8&2
T - 9&3
There are also 3 other sets of common pairs, lets call them U, V, &W
U - 4&10
So the trick is to adjust the wireing from R,S,&T to the line and U-V-W tied together to R-W, S-U, T-V pairs connected to the line voltage.
I would bet you have a motor starter and some kind of secondary contact that automaticly switches already set up in your control pannel. You just need to look for it.
Looks like some kind of contactor with 3 normaly open contacts and three normaly closed contacts in conjunction with a timer or current sensing relay could handle this
It will have at least six in and out taps plus taps to control the coil. Its very likely it will have more than six taps if its electricly interlocked to other circuts.
My ignorance is why this type of start/run configuration is desireable.
Why put the money into extra relays and switch gear when Y or Delta wound motors will start up without all this switching?
I am going to guess it has something to do with limiting the starting current or improving the starting torque, but that is just a wild guess.
12-14-2011, 04:48 PM #7
This is a motor designed for wye - delta starting. The motor is wired in wye to start and then switched to delta to run. Used to reduce the inrush current. I am surprised to see this on such a small motor, most of the ones I am familiar with on two to six hundred ton chillers. Possibly designed to work with manual compensators.
12-14-2011, 05:39 PM #8
The Camut and Blanchard grinders I have worked on recently both have the wye start, delta run configuration. The 100 hp motor on the Blanchard soft starts on wye, then to delta and has DC braking that comes on a couple seconds after the main contactor opens to be sure they aren't on at the same time and then shuts off after enough time to stop. With a steel wheel holding insert stones along with the motor armature there is enough inertia that it will coast for a very long time without braking. It takes 4 big contactors and three timers to do all that but without it rundown time could put a real dent in production. All this sturm und drang is worthwhile on a machine like that, but as Tom says, it doesn't make much sense on a 5 hp motor.
12-15-2011, 04:52 AM #9
me being graphicaly challenged
it would be
1-2-3-4-5-6 in a wad
run on low voltage with conventional motor controls
screw the "start thing"
12-15-2011, 05:59 AM #10
12-15-2011, 08:08 AM #11
Makes perfect sense to me also.... just look at the coil voltages and polarities.... (terminal numbers).
This being an asian motor, are you sure I shouldn't lock this?
(I know, the description fits actual shop equipment.... so OK)
12-15-2011, 10:18 AM #12
12-15-2011, 10:27 AM #13
my home shop band saw is 9.5 feet tall.
Some home shops are more interesting than others.
12-15-2011, 12:02 PM #14
If you want more on wye - delta starters, do a search term of "wye - delta staters" on Google. You will find that there are two types, open and closed transition. Closed transition is designed to maintain flux in the motor in phase with the power line to avoid current spikes when the delta contactor closes. Because of the amount of, and complexity of, the control circuit, this type of starter is normally only used where there are restrictions on the inrush current.
If you want reduced inrush starting which achieves the same purpose, look at auto-transformer, primary resistor or part winding. Part winding is kind of a special, since it uses a dual winding motor, such as a 480/240V motor wired for 240. Because only half the windings are used for starting, the torque is quite low.
Regarding the current inquiry, I would wire the motor in delta and use a cross the line starter.
12-15-2011, 12:04 PM #15Low Voltage Delta
R = 1,6,7,12
S = 2,4,8,10
T = 3,5,9,11
looks like i let the smoke out again
i see it
now that i see it
12-15-2011, 12:38 PM #16
12-15-2011, 07:01 PM #17
12-16-2011, 09:13 PM #18
"...even then some smartass would conjure up an exception I forgot to mention..."
I resemble that remark...
The 12 wire thing, consider the dual-voltage version of the hardinge two-speed
motor. That rare item does indeed have 12 wires to make it all happen. I think
the hardinge is probably consequent pole, but it can be drawn as star/delta the
same way that one above is.
There must be a very complicated contactor to do the start/run operation on that
chicom drill. Excuse me, taiwanese.
Oddly, I've always considered taiwan to be a technical leader, probably from my
encounters with folks from that country, where I work.
12-18-2011, 09:16 AM #19
Inrush is ONE reason...
But there's another reason why Y-D starting is used, and even in smaller applications.
When a motor is started, there's a very high inrush applied to the windings in order to build flux.
During this timeperiod, the windings and core can build quite a bit of heat... but you typically won't 'feel' it on the outside of the motor case, because the heat is DEEP.
If you look at the nitty-gritty specs on motors, you'll see that true industrial specs always include things like Service Factor, Power Factor, and STARTS PER HOUR.
The latter, is one of the biggest reasons for Y-D... by using Y-D, the deep heating of start inrush is cut dramatically, allowing the motor to be started and stopped a whole lot more frequently, than if it's run in straight D.
So if you're doing lots of repeat cycles, the Y-D start is a necessity. One place where Y-D start appears almost exclusively, is in hydraulic passenger elevators... the hydraulic power unit is called upon to push the cab up, and the motor is stopped on the down-cycle. Restarted on up, stopped on down. The Motor Run contactor is frequently controlled by microprocessor or time-delay relay to keep the motor running for a short period of time after making the last commanded station landing, so that if an oncoming passenger selects a higher floor, it will avoid a stop/restart at the motor... and if they select a DOWN, the controller goes into down-mode, and the pump motor is allowed to shutdown. Now, the hydraulic power unit is starting against a fixed-volume pump, so motor start occurs under a certain amount of physical load, but many control valves have a partial-unloader function to bypass pump pressure below a certain volume (function also locks the output circuit to prevent unintentional backflow for cab safety). If it weren't for Y_D start, the hydraulic unit would need a motor substantially larger, just to withstand the starts-per-hour demands, and of course, the larger motor would eat even more power, and really blink the lights in the Holiday Inn Express.
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