Ldpu Volumetric Capacity Adjustment Methods; Adjustment Of The Volumetric Capacity With The Inverter; Adjustment Of The Volumetric Capacity Via Mechanical Speed Controller - OMAC B Series Operation And Maintenance Manual

Rev.4 del 01/2011 O.M.A.C. s.r.l.

4.3 LDPU volumetric capacity adjustment methods

On the basis of the production needs of the Customer, one can adjust the power supplied by the LDPU. The adjustment of the volumetric capacity of the
LDPU can be carried out in two ways:
• acting on the inverter adjustment, if the LDPU is equipped with an inverter;
• acting on the speed controller hand-wheel adjustment, if the LDPU is equipped with a mechanical speed controller.

4.3.1 Adjustment of the volumetric capacity with the inverter

This operation, i.e. the variation of the electric motor speed via inverter, must be carried out by the operator in charge of running the plant: he must rotate
the speed adjustment potentiometer knob on the electric panel, setting it on the desired frequency value, expressed in Hz.
The result of the frequency adjustment, with the potentiometer, translates in a speed variation of the electric motor revolutions and consequently in a
capacity variation of the LDPU.
The operator must read the consequent volumetric capacity variation on the meter placed on the delivery piping near the LDPU (see stage 2 section
3.3.3).
It is assumed one has an electric motor that supplies a current number of output revolutions, N
50 [Hz] and that we will indicate more in general with F
with which the inverter must be set, f
4.3.2 Adjustment of volumetric capacity via mechanical speed controller
This operation, i.e. the speed variation of the speed controller, must be
carried out by the operator in charge of running the plant:
he must act on the mechanical speed controller hand-wheel, only after
having started the LDPU.
WARNING
Adjust the mechanical speed controller hand-wheel,
only after having started the LDPU. The adjustment of
the speed controller must not be carried out with the
machine off as it can cause the breakage and malfunc-
tioning of the speed controller.
Before adjusting the hand-wheel, read the value the speed controller is
set on, in the hand-wheel panel. The hand-wheel panel is shown
in fi gure A. Below, in the table placed to the side as an example, one can
obtain the value of the LDPU revolutions.
For example, if we are in presence of a size "10" speed controller and
the hand-wheel (fi gure A) has the arrow on 5, simply trace a vertical
line, starting from the column corresponding to the "10" size, until 5,
indicated by the hand-wheel, to then proceed horizontally, towards the
left until reading the corresponding number of revolutions at which the
speed controller operates, i.e. 450 RPM.
1
2
3
4
5
6
7
8
9
fi gure A
Frequency calculation.
. Assuming one wants to obtain a different number of output revolutions N
current
will be equal to: f = (F
new new current
0
19
18
17
16
15
14
13
12
10 11
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at the national electric network frequency, equal to
current
* N )/ N
new current
12
1000
11
950
9 10
900
850
9
8
800
8
750
7
700
7
6
650
6
600
5
550
5
500
4
4
450
400 3
3
350
2
2
300
250
1 1
190 0 0
03 05
QUANTITIES REFERRED TO
GRANDEZZE RIFERITE AI VARIATORI
MOTOVARIO/SPAGGIARI
SPEED CONTROLLERS
O.M.A.C. s.r.l.
Tel.0522/629371 - 629923 Fax 0522/628980
the frequency
new
25
15 17 21.5
21
24
14 16
20
23
15
13 19
22
14
18 21
12
13
20
17
11
12 19
16
11 18
10
15
17
10
14
9
16
9
13 15
8
14
12
8
7 13
11
7 12
10
6
11
6
9
10
5
8
5
7
4
4
6
3
5
3
4
2 2
3
2
1 1
1
0 0
0
10 20 30-50
MOTOVARIO/SPAGGIARI
Chap.4 - pag.
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8
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6
5
4
3
2
1
0
100
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