Motor Compatibility - Control Techniques Focus 3R User Manual

Motor Compatibility

The Focus 3 was designed to run standard 90 Vdc or 180 Vdc Shunt Wound or Permanent
Magnet DC motors in both directions.
(such as Universal motors) but one must review those requirements to insure compatibility.
Universal motors have commutator brushes but typically plug into the AC power line. Universal
motors are often used in tools such as Drills, Saws, Shop VAC's, Routers, etc and typically
cannot be run in reverse.
Shunt Wound Motors that are controlled by single phase DC drives typically have 4 power
wires. Two of these are the Armature leads typically designated A1 & A2 or A+ & A-.
other two power wires are the shunt field leads and typically designated F1 & F2 or F+ & F-.
The Focus 3 can supply up to 1 Amp for shunt field excitation (field current requirements
beyond 1A may damage field rectifier diodes).
information on the nameplate, you can determine compatibility by measuring your motors Field
resistance using a calibrated ohmmeter.
Motors with:
90v Armatures typically require 100 Vdc for field excitation. In these cases, the Focus
3 requires 120vac input power and must be internally set for this input level. The motor
Field resistance should not be less than 100 ohms when cold.
180v Armatures typically require 200 Vdc for field excitation. In these cases, the Focus
3 requires 240vac input power and must be internally set for this input level. The motor
Field resistance should not be less than 200ohms when cold.
The motor nameplate information is key to determining compatibility. As seen below,
the motor below easily falls in the range of the Focus 1 operated from a 240vac supply.
The drive will supply 180v for the armature and 200v for the field ( this motor indicates
there are 2 field windings and for 200vdc they must be wired in series ). The field
current requirement is 0.28A which is well under the 1A maximum.
1
240v Armatures typically require 150 Vdc for field excitation. In these cases, the Focus
3 requires 240vac input power and must be internally set for this input level. The motor
field resistance should not be less than 150 ohms when cold and will require a series
resistor to drop the additional field supply voltage. Consult Control Techniques Technical
Support for additional information.
The Focus 3 can run motors with other characteristics
1750 / 2050
5.0
0.28/.22
If your motor does not have Field Current
180
SHUNT
518
FLD VOLTS 200/100
The
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