What is a tach output? Top
A tach output or "sensor output" as shown in the catalog indicates the speed of the fan at different operating levels. Its purpose is to identify when the fan drops below a certain RPM, and to identify a potential problem with airflow. A tach output fan will always have at least 3 wire leads.
	What is a locked rotor? Top
A locked rotor is also a type of "sensor output" that measures when the fan has completely stopped or "locked." It sends a signal, frequently called an alarm signal, at either high or low voltage when the rotor locks. If the fan starts spinning again, the alarm signal condition will go away. This is known as a non-latching locked rotor signal, which is standard with TEI fans
	What`s the purpose of a temp sensing fan? Top
A temp sensing fan is designed to respond to changes in temperature within a customer`s system. Basically, as the environment gets hotter, the fan works harder to cool the system by delivering more air. A fan works harder by increasing its RPM, which then increases airflow.
	What are the different ways a temp sensing fan can be controlled or configured? Top
There are 3 basic options TEI offers: 1) a hub mounted thermistor, 2) a remote third lead wire with a thermistor on the end, or 3) a remote 3rd lead with voltage controlling the speed of the fan.
	What information do we need from the customer to build a temp sensing fan? Top
Hub mounted thermistor: Engineering needs to know the performance needed at a given temperature. This is typically illustrated with a temperature versus RPM curve. Remote temp sense thermistor controlled( 3rd lead wire): Engineering needs to know need the resistance (in Ohms) versus RPM. A curve is the best way. Remote temp sense voltage controlled: Engineering needs to know the performance (RPM) at different voltages. The voltage range we offer is from 0-6 volts. This is for the control lead only and should not be confused with fan operating voltage.
	What is the voltage range for DC fans? Top
It varies depending on the type of fan and voltage. Check the catalog for voltage ranges.
	What is the voltage range of our AC fans? Top
The voltage range is +1-10 % of nominal.
	Do AC fans have special control features (tach out, locked rotor, temp sense)? Top
AC fans do not come with the special control features. AC voltage pattern does not allow same versatility as DC.