Fire alarm vfd shutdown

Learn the NEC with Mike Holt now!
Status
Not open for further replies.

fireryan

Senior Member
Location
Minnesota
I’m using a addressable fire alarm relay to shut down a vfd. Is the best way to achieve this by running the enable circuit thru the dry contacts on the relay?
 

Jraef

Moderator, OTD
Staff member
Location
San Francisco Bay Area, CA, USA
Occupation
Electrical Engineer
That’s probably the best way because by using the enable circuit, you override any ramp down or braking settings and immediately kill power to the motor, which is what you often want in an emergency, especially on a pump or fan.

If the machine is of a type that can benefit from braking being done via the VFD however, like a conveyor or a centrifuge, keep that in mind because that may dictate using a regular Stop command.
 

gadfly56

Senior Member
Location
New Jersey
Occupation
Professional Engineer, Fire & Life Safety
That’s probably the best way because by using the enable circuit, you override any ramp down or braking settings and immediately kill power to the motor, which is what you often want in an emergency, especially on a pump or fan.

If the machine is of a type that can benefit from braking being done via the VFD however, like a conveyor or a centrifuge, keep that in mind because that may dictate using a regular Stop command.

If killing the power to a machine or device rather than using a shutdown procedure would cause a greater risk to the public, then you are allowed to send the signal to a controller. Think elevator recall. The same would go for an escalator or moving walkway.
 
Status
Not open for further replies.
Top