6 replies to this topic

[AB2005]

Dear friends;

We have a die cut machine where an old wound rooter variable speed motor (6-20HP) is installed which we want to replace with a simple AC motor 30KW, 4poles. The motor drives a flywheel (almost 500KG) and then a clutch engages the flywheel with machine. For variable speed operation, we want to control the speed of new motor via an inverter drive (Mitsubishi) but problem is that if, for example, motor is rotating at 1000Rpm and we slows down the speed, the flywheel (which is rotating at 100Rpm too) will be restricting to motor to slows down in desired time. For this problem, we are going to connect a Brake Resistor to achieve the quick deceleration.
Am I working in right direction? Any other suggestion/idea?

[yuri]

Dear friends;

We have a die cut machine where an old wound rooter variable speed motor (6-20HP) is installed which we want to replace with a simple AC motor 30KW, 4poles. The motor drives a flywheel (almost 500KG) and then a clutch engages the flywheel with machine. For variable speed operation, we want to control the speed of new motor via an inverter drive (Mitsubishi) but problem is that if, for example, motor is rotating at 1000Rpm and we slows down the speed, the flywheel (which is rotating at 100Rpm too) will be restricting to motor to slows down in desired time. For this problem, we are going to connect a Brake Resistor to achieve the quick deceleration.
Am I working in right direction? Any other suggestion/idea?

Provide for pauses in the process engaging the clutch in the idle turns – without the material processed – to slow down the flywheel, so to say “naturally,” when going to a lower speed.

[jOmega]

Dear friends;

We have a die cut machine where an old wound rooter variable speed motor (6-20HP) is installed which we want to replace with a simple AC motor 30KW, 4poles. The motor drives a flywheel (almost 500KG) and then a clutch engages the flywheel with machine. For variable speed operation, we want to control the speed of new motor via an inverter drive (Mitsubishi) but problem is that if, for example, motor is rotating at 1000Rpm and we slows down the speed, the flywheel (which is rotating at 100Rpm too) will be restricting to motor to slows down in desired time. For this problem, we are going to connect a Brake Resistor to achieve the quick deceleration.
Am I working in right direction? Any other suggestion/idea?

AB2005,

There is too much information/detail that you have not provided so it is impossible to answer your question. with any authority.


Sorry.

[marke]

we are going to connect a Brake Resistor to achieve the quick deceleration

This will work provided that the brake resistor is specified correctly, but you may also consider a regenerative VFD such as an active front end VFD as the brake energy will be returned to the supply and reduce your running costs.

Best regards,
Mark.

[yuri]

! What simpler and more effective deceleration may be there achieved as not in the idle stroke of the machine (maybe a partial stroke) - in which time there is no material (metal?) being processed – and in which the kinetic energy of the flywheel would be absorbed, by the machine itself., thus reducing the flywheel speed to the desired , lower, level ?

[AB2005]

AB2005,

There is too much information/detail that you have not provided so it is impossible to answer your question. with any authority.

Sorry.

Dear jOmega;

What kind of more information you require to answer this question? Please list down I will try to answer.

Mark's idea is also good to use a active front end VFD.

[Merlin26860]

AB2005, we have had a similar issue and there are a few points to note. Our application was on a 70 ton press and the VFD would trip on High DC Volts when trying to slow the motor down. A braking Resistor did solve this problem and you should consult the manufacturers book for the correct sizing. The other issue you may have, is when the clutch engages and the drive may trip on Under volts. This is obviously from the motor trying to accelerate the flywheel. This was apparent to us when the operators ran different dies. the small dies would trip on High Volts and the large dies on Low Volts. Make sure there is a protection function in the braking resistor circuit such as a TOL or drive software etc. It may save a fire if your application requires a lot of braking. I'm not sure about the cost effectiveness of a Active front end drive seeing this is only a 30kW motor, but worth the excersice.
Good Luck

Dear friends;

We have a die cut machine where an old wound rooter variable speed motor (6-20HP) is installed which we want to replace with a simple AC motor 30KW, 4poles. The motor drives a flywheel (almost 500KG) and then a clutch engages the flywheel with machine. For variable speed operation, we want to control the speed of new motor via an inverter drive (Mitsubishi) but problem is that if, for example, motor is rotating at 1000Rpm and we slows down the speed, the flywheel (which is rotating at 100Rpm too) will be restricting to motor to slows down in desired time. For this problem, we are going to connect a Brake Resistor to achieve the quick deceleration.
Am I working in right direction? Any other suggestion/idea?