Instruction manual

INSTRUCTION MANUAL UGG023-0107 CGW Granulators
DESCRIPTION
2:18
Current relay
2. DESCRIPTION
General rules, Current relay
The granulator may be provided with a current relay
(optional). The current relay monitors the granulator’s
current consumption.
As the granulator’s current consumption exceeds the
upper current level (LVA), the current relay trips and
stops the feed equipment (such as a band conveyor or a
roll feed).
The current relay is preset to automatically restart the
feed equipment as the current consumption has sunk to
the lower current limit (HA).
Limit value ( LVA, LV%)
The limit value (LVA) is the preset current consumption
level where the current relay trips and stops the feed
equipment.
The limit value is adjustable. The limit value’s adjusting
knob is graded 0–100%.
The limit value in Ampere (LVA) is calculated as shown
in the LVA-formulas on the right. Note! LVA is calculated
differently as the granulator is “Y/D-started” or “Direct-
started”.
The limit value percentage (LV%) is calculated as shown
in the LV% -formula on the right.
The electrical circuit diagram shows the rated current and
the current transformer’s size in the supplied machine.
Hysteresis ( HA, H%)
The hysteresis is the preset current consumption level
which determines when the current relay shall reset and
restart the feed equipment.
The hysteresis is adjustable. The hysteresis’ adjusting
knob is graded 5–50%.
The hysteresis percentage (H%) applies to the limit value.
The hysteresis in Ampere is calculated as shown in the
HA-formula on the right.
Reaction time (T1)
The reaction time is the preset period of time that
determines how long the current consumption shall
exceed the upper current level (LVA) before the current
relay shall trip and stop the feed equipment.
The reaction time is adjustable. The reaction time’s
adjusting knob is graded 0.1–3.0 sec.
(G)
Excess current
Memory OfMemory On
Undercurrent
(A)
(B)
(C)
(D)
(E)
(F)
(G)
(A) = Limit value percentage, LV%
(B) = Reaction time, T1
(C) = Time delay, T2
(D) = Hysteresis percentage, H%
(E) = Yellow LED, Current consumption
(F) = Green LED, Control voltage
(G) = Function settings
LVA (Y/D-start) = Rated current / √3
LVA (Direct-start) = Rated current
LV% =
( LVA x 100 )
Current transformer size
HA =
LVA – ( LVA x H% )
100
Continued