Installation check – Grain Systems Bin Accessories PNEG-524 User Manual
Page 25
7. Electrical Installation
PNEG-524 Roof Exhaust Fan
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Fan Disconnect
A disconnect for the fan needs to be sized to handle the recommended fusetron size. Example: For a
24" fan the first chart
would be used and the fusetron size is 30 Amp. Install the fusetron
recommended in the disconnect. A circuit breaker can be used, however, the circuit breaker or any fuse
used must be a time delay type to allow the initial starting inrush current to the fan.
Conductor Size for the Fan Disconnect to Fan Wiring
The conductor size for the fan needs to be sized according to the distance between the fan and
disconnect. Example: For a 24" fan located 200' from the disconnect use the first chart
to determine the conductor size to be a 14 AWG. The proper size wiring must be used to make sure a
voltage drop does not occur.
Fan Motor Controller
Size the fan motor controller according to the motor ratings for a convenient control location as follows:
• Motors with internal overload protection will require a magnetic contactor to control fan operation.
• Motors without overload protection will require a magnetic starter with overload protection to control
fan operation.
1 Phase
A 3 wire system should be provided for fans to be operated on 1 phase power. The three (3) wires consist
of the two (2) current conductors and a ground. The current carrying conductors are wired per the diagram
on the motor. The ground is secured to the motor frame. On 2 HP explosion-proof motors thermostat wires
are provided with the motor and must be connected to the fan motor magnetic controls.
3 Phase
A 4 wire system should be provided for fans to be operated on 3 phase power. The four (4) wires consist
of three (3) current carrying conductors and a ground. The current carrying conductors are wired per the
diagram on the motor. The ground is secured to the motor frame. On 2 HP explosion-proof motors
thermostat wires are provided with the motor and must be connected to the fan motor magnetic controls.
When installing electrical service for explosion-proof motors make sure all conduit and connectors
exposed to the conditions of the motor are rated for the Class II Group F and G location of the motor.
Installation Check
When the fan is completely assembled and wired, the unit needs to be checked for proper rotation. Provide
power to the fan controls and start the fan momentarily. Make sure the fan blade rotates to exhaust air
from the bin. If the blade is rotating in the wrong direction, have the electrician correct as follows:
1 Phase System
With the power OFF at the fan disconnect, the motor lead wires at the fan motor need to change
as indicated on the motor to reverse the blade rotation. The unit then needs to be re-checked for
proper rotation.