Tyre Building Machine Motor - Strange rating plate
Tyre Building Machine Motor - Strange rating plate
(OP)
I have received a 3-speed induction motor used in automative tyre building machines.
The motor name-plate states 5.5/3.5/0.6 KW at 945/555/165 RPM with corresponding currents of 16/17.5/20 Amps, which didn't seem right.
So, I asked the client for the load cycle currents at each speed and he confirmed the ratings as below
Normal Currents
Low speed 20 to 24 A
Medium speed 8 to 11 A
High speed 4 to 6 A
Forward to reverse cycle currents (duration 9 seconds each)
Low speed 25 To 30 A for 9 sec
Medium speed 25 To 30 A for 9 Sec
High speed 60 To 70 A for 9 Sec
No. of reversals in one cycle of 12 minutes
Low speed 2 times
Medium speed 1 time
High speed 4 times
Questions:
What type of load (torque-wise) that would take such high currents at low speeds ?
And why does the name-plate show lowest KW rating with the highest current ?
The client reports they have multiple tyre building machine motor failures in a year and I am supposed to stop that. !!!
The motor name-plate states 5.5/3.5/0.6 KW at 945/555/165 RPM with corresponding currents of 16/17.5/20 Amps, which didn't seem right.
So, I asked the client for the load cycle currents at each speed and he confirmed the ratings as below
Normal Currents
Low speed 20 to 24 A
Medium speed 8 to 11 A
High speed 4 to 6 A
Forward to reverse cycle currents (duration 9 seconds each)
Low speed 25 To 30 A for 9 sec
Medium speed 25 To 30 A for 9 Sec
High speed 60 To 70 A for 9 Sec
No. of reversals in one cycle of 12 minutes
Low speed 2 times
Medium speed 1 time
High speed 4 times
Questions:
What type of load (torque-wise) that would take such high currents at low speeds ?
And why does the name-plate show lowest KW rating with the highest current ?
The client reports they have multiple tyre building machine motor failures in a year and I am supposed to stop that. !!!





RE: Tyre Building Machine Motor - Strange rating plate
RE: Tyre Building Machine Motor - Strange rating plate
Bill
--------------------
"Why not the best?"
Jimmy Carter
RE: Tyre Building Machine Motor - Strange rating plate
RE: Tyre Building Machine Motor - Strange rating plate
Is this a job for a VFD? If you remove two windings you may have room for one very robust high speed winding.
Bill
--------------------
"Why not the best?"
Jimmy Carter
RE: Tyre Building Machine Motor - Strange rating plate
But the 9 second currents are apparently the result of plugging the motor forward-to-reverse and vice versa and this occurs seven times in 12 minutes. If I've got this right, this is going to control the sizing of the motor and the drive.
Under the above conditions, I would choose (or wind) a 7kw 8-pole motor and run it overspeed to get the 945rpm. I would choose a sensorless vector drive with a 1 minute rating at least three times the motor FLA. If I had the choice, I would use a TENV enclosure for the motor with Class H insulation and, if not practical, go with TEFC with the largest practical fan.
I doubt that a regenerative drive would pay back at this small size so I would go with a full-capacity snubber brake package. The resistor will need to be right at minimum ohms for the drive brake chopper rating and the resistor wattage will be about 4kw.
I'm sure someone out there will see this differently. Let's discuss.