Tach Generator Wiring; Low Voltage Wiring; High Power Wiring; Traveling Cable Wiring - O. Thompson Microflite Ultra 2000 Installation & Adjustment Manual

D) Continuous wire from the isolation transformer frame to the single ground stud
(SCR jobs only)
E) Continuous wire from the DC choke frame to the single ground stud (SCR drive
only)
F) Continuous wire from the line filter frame to the single point ground stud (AC Vector
jobs only)
G) Jumper the "N" stud on the line filter to the line filter frame.
H) Continuous wire from the load reactor frame to the single point ground stud.
I) Continuous wire from the drive frame ground stud to the single point ground stud.

4.1.4 Tach Generator Wiring

The tach generator signal is the heart of the generator shunt field regulator. This signal must be
as clean as possible or extreme instabilities may occur in the motor drive system. Instabilities
caused by a noisy tach signal can take days of adjustment to filter out of regulator circuits. It only
takes a couple of hours to run a separate pipe for the tach.
The tach signal should also be wired using a shielded twisted cable with the shield terminated to
the controller ground terminal on the controller. DO NOT ground the shield on both ends of the
cable. If the shield is grounded at both ends, an "antenna" is created, and more noise can
be induced into the tach signal than if the shield were left completely ungrounded.
4.1.5 Low Voltage Signal Wiring
Low voltage signal wiring includes all the 24 volt inputs. These include the car calls, door limits,
electric eyes, etc. The inputs on the I/O boards only need to see 12 volts or more to turn on. If the
signal wires are run along side the 240 VDC door operator wiring, a 12 volt spike is very likely to
occur. Keep low level signal wiring run at least 4 inches away from high power wiring to avoid false
signal firing. Wherever this is not possible, and the low level wiring must cross the high power
wiring, the two should cross at ninety degree angles to each other.

4.1.6 High Power Wiring

High power wiring that should be piped separately from all other signal wiring include the following:
Main line connections to the cabinet.
Motor armature and motor field wiring.
Brake coil wiring.
Generator Shunt Field wiring.
Generator Armature wiring.
In most cases it is practical to run the motor armature, motor field, and brake wiring in one pipe.
The other wiring should all be run in separate pipes, and NOT run in the common duct with all the
signal wiring.

4.1.7 Traveling Cable Wiring

Although we have not yet experienced problems in this area, it is always best to consider the worst
case scenario and try to avoid potential noise induced problems in the signal wiring.
When laying out traveling cable wiring, it is always best to have the low voltage signal wiring
multiple layers away from any 14 AWG power wires used in the traveling cables.
Revision: AA 2.2
Microflite Ultra 2000
Printed 03 - 15 - 03 4 - 3