Advice on 2 speed crane wiring

[eeprom]

Hello,
I received some German wiring for a shop crane. For the trolley, there are two speeds used, no VFD. So the speed control must be done by adding or removing poles. I am stumped as to how the speed control works.

The wiring has 6 leads to the motor, labeled 1, 2, 3, 4, 5, 6. These wires are shown on the dwg as 2 parallel sets of three phase power to the motor.

The wiring at the motor is shown as (from the left) U1, V1, W1, and (from the right) U2, V2, W2.

Wires 1, 2, 3 are phases ABC, and wires 4, 5, 6 are also phases ABC. 1 is jumpered to 3; 2 to 4, and 3 to 6.

Downstream of the jumpers is one 4 pole contactor, making or breaking wires 2, 3, 4 and 5. On wires 2, and 3 there is a NO contact labeled (FAST). On wires 4 and 5 are the NC contacts of the FAST contactor. There are no contacts on wires 1 and 6, so these are always energized (assuming the motor is on).

So when FAST is energized, the wires 1, 2, 3, and 6 are energized, or phases A,B,C, and C are energized, (or U1, V1, W1, and W2 are energized). When FAST is not energized, wires 1, 4, 5, 6 are energized (or U1, U2, V2, W2).

I don't know how many poles the motor is, but let's just assume 4. I have been looking at diagrams ( in the Robert Rosenberg, August Hand book) on how to wire a motor to switch it from 4 poles to 8 poles, thereby cutting the speed in half. But I cannot see how the wiring I have could possibly result in this.

Can someone please explain how the wiring configuration explained here can result in two speeds on a 3 phase motor?

thanks for your help
EE

 

[petronila]

Hello eepron,

The electric motor speed could be controlled by many ways:

1.Changing the frequency with VHF, but is not the case.
2.With the use of PAM motors.
3.With Dahlander motor.

Suggestion: Take a look of the motor name plate and Verify the power and speed.

Q: is the low speed the half of the high speed? if yes (And I think is your case) the germans are ussing a Dahlander motor, this connection could be done for 3 cases: i. Constant power ii.Variable Torque and iii. Constant torque. Take a look of the attachment.

Like is explained in the sketchs, depending of the case always you will need to connect the motor wires with contactors in order to change the motor connection from low to high speed or hgh to low speed.

Regards

Carlos

 

[eeprom]

petronila,
Your attachment is the same wiring I was referring to in my post. I understand that this wiring switches from 8 poles to 4 poles. But your theory (and mine) does not fit the wiring I have. There is a total of 6 leads going to the motor, and one 4 pole contactor for switching the motor leads. 6 wires to the motor, in order of phasing: A1, B1, C1, A2, B2, C2. A1 is jumpered to A2; same for other phases. The B1 and C1 are routed through NO contacts of a speed control contactor. A2 and B2 are routed through NC contacts of the same contactor. There are no contacts available to reconfiguring motor lead connections.

Unfortunately the motor has not arrived yet, so I have no information on the motor.

Also, why do they call it a Dahlander motor? This configuration can be done with any twelve lead motor.

 

[petronila]

Hello eeprom,

You can not run a 12 lead standard motor like a Dahlander that´s because Low voltage connection is the double of high voltage connection (2Y-Y), (2D-D)and it´s winding designg don´t let do that. In Dahlander case the winding is connected by poles and later in the second speed is connected by consequent poles, you can´t do that in an standard motor because the winding is always connected by pole or by consequent pole (Depending of design).

About your wiring, maybe could be some kind of drum switch, could you provide the manufacturer name?

Regards

Carlos

 

[LionelHutz]

After trying to follow your wiring description, I would suspect it's just a 2-winding motor.

 

[eeprom]

That is an interesting thought. I have the name plate, and it doesn't say the number of phases. The numbers don't add up for 3 phase.

Fast speed
V: 440-480
A: 20A
kW: 11
RPM: 3450

Slow speed
V: 440-480
A: 10A
kW: 1.6
RPM: 440

I've never seen anything like this. Can someone explain how this is wired?

EE

 

[jraef]

You have what I think is a custom motor design. A standard Dahlander motor would be a 2:1 speed ratio. You seem to have something really odd there; it's a smidgen less than an an 8:1 speed ratio (7.84:1?)and the use of a 4 pole contactor is also very odd. That is not any industry standard that I am aware of. So it's doubtful (albeit not impossible) that anyone is going to know what's going on with that, unless perchance they have seen one before.

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[eeprom]

Yes, I think so too. It's a KoneCrane from Germany. I've asked for a motor wiring diagram. I doubt that I will get one. I don't really need it for the installation. But I sure would like to know how they get such a wide speed range.

 

[zlatkodo]

Hi, eeprom,
Sorry, I have not carefully read everything about your motor (scheme is better than all the description), but I think it is a motor with two separate windings.
Unfortunately, there is no other data from the nameplate, but probably, one of the windings is in delta-connection (or connection with more circuits), and therefore there is need to use a NC contact.
Zlatkodo

 

[burnt2x]

eeprom,
I guess what you got is a two-winding motor,as others have said earlier. The high speed winding (11kW) is 2 poles (3,500rpm) while the low-speed winding (1.6kW) is 12 poles (500rpm).
Treat each group of windings separately. One contactor controlling the high-speed run and another contactor for the low-speed run. These two starters are interlocked and designed not to simultaneously energise. I have had motors like that in one of our German-made 40T OHC, a different brand though.