Lennox FCA 60

Page 40 - IOM / ROOF-TOP FLEXY™ Series
VENTILaTION : FANSTART OPERATION
Current protection of the Thyristor
The FANSTART will display a fault (red LED) if the current
exceeds the thyristor current limits
125A during 0.4 s
87.4A during 2 s
75A during 6 s.
62.5A during 20 s.
Start up sequence too long
A fault (red LED) will appear if after 1min20s the FANSTART
Control is not bypassed and the motor running from the mains.
Phase rotation check
If the phase rotation is incorrect the FANSTART Control will
display a fault ( Red LED). Two of the phases must then be
inverted and the start up cycle resumed.
AIR SOCK CONTROL
The use of air socks for space conditioning allows high air
volumes to be distributed at low velocity and is becoming a
common feature in many applications. To accommodate this
trend, Air-sock control is offered which allows the air socks to
be progressively filled with air on start up. FLEXY™ has been
enhanced with an electronic device to soft start the fan. It
takes up to 1 minute to go from 0% of air to full air flow.
This time can be divided in several stages :
- The aim of this first voltage input is to overcome the
resistance of the transmission (Pulleys and belts) : 0.5s
and up to 1000 rpm
- The second stage is to inflate the air sock : 5 to 30 s.
and 600 to 900 rpm
Finally the air sock is gradually pressurised during the last 5
to 30 second. The motor reaches nominal speed and the
controller is bypassed.
The motor speed control is achieve through a variation of the
supply voltage of each phase at constant frequency.
The thermal overload limit on the motor imposes a current
limitation during the acceleration stage. Hence if the selected
slope is to steep, a predefined current limit can be reached
(potentiometer adjustment) and the controller will automatically
reduce the voltage set-point accordingly. Then once the current
is back under the high current limit it carries on with the start
up cycle.
Safety
Excessive "slow down" limit
The FANSTART will display a fault (red LED) and stop the
motor, if the motor slows down excessively (voltage could
reach 0V) because of the current limitation during the
acceleration stage.
Missing phase safety
The FANSTART will display a fault (red LED) if the current in
the third phase is too low or reaches 0 Amps (Three phase
supply or motor problem)
FAN START
OFF
MOTOR OFF
Green LED = 0
Red LED = 0
MOTOR OFF
Green LED = 1
Red LED = 1
Power + Control ON
Green LED = 1
Red LED = 0
Control ON
Power OFF
PHASE
ROTATION
CHECK
T°C Fault
Thyristor
OK
INFLATION
Green LED = 1
Red LED = 0
ACCELERATION
Green LED = 1
Red LED = 0
(If current control ON)
CONTROL OFF
motor connected
to mains
NOT OK
I > I max
Speed = 0
T > 1 min20s
I < Imin
I > I max
Speed = 0
T > 1 min20s
I < Imin
Current
1
st
voltage Input to Overcome
transmission performance
Over-current limit
Air sock
Inflation
5 to 30s
Acceleration 15 to 30s
FANSTART off
Figure 35
Figure 37