Method and apparatus for controlling reel tension

Details Method and apparatus for controlling reel tension Method and apparatus for controlling reel tension

1985-09-12

1988-01-19

Ro, Bentsu

Electricity: motive power systems

With particular motor-driven load device

Tension-maintaining type of motor-control system

242 7551, 364473, H02P 706, B65H 5938

Patent

active

047206616

DESCRIPTION:

BRIEF SUMMARY
TECHNICAL FIELD

The present invention relates to a method and apparatus for controlling the tension of a reel driving motor which is used to drive a reel for taking up or rewinding material in a rolling machine processing line, rubber or plastic manufacturing equipment, or similar equipment and, more particularly, to a method and apparatus for controlling reel tension which is suitable for enlargement of the tension control range.


BACKGROUND ART

Hitherto, apparatuses for controlling reel tension in rolling machine processing lines, rubber or plastic manufacturing equipment, or similar equipment have been constituted by a DC motor,. an electric power converting apparatus and a field power source tension control circuit.
A tension control method of a reel driving motor using a DC motor will be described hereinbelow. A generating torque T.sub.M of the DC motor and a necessary torque T.sub.M ' upon take-up operation are respectively expressed by a take-up tension, D is a diameter of a coil, and K.sub.1 and K.sub.2 are constants. The relation among the take-up tension T, field magnetic flux .phi., coil diameter D, and armature current I.sub.a will be represented by ##EQU1## assuming that equations (1) and (2) are equal. On the other hand, a counter-electromotive voltage E of the DC motor is expressed by addition, the relation of of the motor
From equations (4) and (5), ##EQU2## is satisfied and from equations (3) and (6), ##EQU3## is satisfied, where K.sub.4 is expressed by ##EQU4##
It will be appreciated from equation (7) that the take-up tension T is proportional to the armature current I.sub.a by making the take-up speed v be proportional to the counter-electromotive voltage E. Namely, the tension control in the reel driving motor using the DC motor is performed by controlling the armature current I.sub.a by making the take-up speed v be proportional to the counter-electromotive voltage E.
Conventionally, various kinds of devices have been made to extend the tension control range; however, all of them fundamentally perform the tandem drive and an example of such a driving method as a prior art is shown in FIG. 2. In this tandem drive, two motors M.sub.1 and M.sub.2 are connected through a clutch 4 and the motors M.sub.1 and M.sub.2 are controlled through motor control circuits 2 and 3 in response to a command from a tension control circuit 1, thereby controlling the reel tension. The two motors M.sub.1 and M.sub.2 are used in case of the high tension control, while the clutch 4 is released and the single motor M.sub.1 is used in case of the low tension control, thereby controlling the tension of a reel 6.
A principle of enlargement of the tension control range due to such a tandem drive will now be described with respect to the cases where the two motors M.sub.1 and M.sub.2 have the same rating and where they have the different ratings. same:
In the case of rolling machines, a range of the armature current I.sub.a which can be accurately set and controlled is generally 1:10 to 1:15 at a current command level. When the setting and controlling range of the armature current I.sub.a is set to 1:10, the setting and controlling ranges of the armature current I.sub.a in the cases where the two motors M.sub.1 and M.sub.2 are coupled and where only the motor M.sub.1 is used will be as follows, if the sum of the rated armature currents when the motors M.sub.1 and M.sub.2 are coupled is 100%.


______________________________________ I.sub.a max I.sub.a min ______________________________________ When the motors M.sub.1 and M.sub.2 100 (%) 10 (%) are connected: When only the motor M.sub.1 50 (%) 5 (%) is used: ______________________________________ I.sub.a becomes armature current I.sub.a which is twice that in the case where one motor is used. of the motor M.sub.1 :
Similarly to the foregoing case of (1), the setting and controlling range of the armature current I.sub.a is set to 1:10 and the capacity of the motor M.sub.1 is set to be 1/4 of the capacity of the motor M.sub.2. The se

REFERENCES:
patent: 3814310 (1974-06-01), Safiuddin et al.
patent: 4519039 (1985-05-01), Surana et al.
patent: 4532597 (1985-07-01), Safiuddin et al.

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