10
Section 2
Equipment Description
Introduction
The DCD Line adjustable speed drive is an integral
combination of an air-cooled magnetic clutch and an AC
motor. Models covered in this manual use a C-Face or D-
Flange, AC induction motor attached to the input end of
the clutch housing. The input member of the clutch is a
steel drum that is driven at a constant speed by the AC
motor. The output member of the clutch is a rotor and
shaft assembly that is driven by a magnetic field that
transmits torque from the drum to the rotor. The magnetic
field is created by a clutch excitation coil that is energized
by an electronic speed or torque controller that provides
the necessary DC coil excitation. The various size units
available are similar in design, construction, performance
and appearance.
Ratings and Model Numbers
A magnetic clutch is simply a torque transmitter.
Appropriate clutch frame sizes have been selected for
various standard motors by matching the torque ratings of
the motors to the clutch ratings, taking into consideration
starting torque, overload torque, speed range and thermal
limits. The resulting motor and clutch combinations
comprise the adjustable speed drive product line.
Standard horsepower and speed range selections,
specifications, application engineering data and outline
drawings can be found elsewhere in this section of this
manual. Tables list the horsepower ratings, speed ranges
and model numbers for various drives covered by this
manual. The model numbers consist of a two-letter prefix
followed by a hyphen and a six-digit number, then another
hyphen and a four-digit number. The following paragraphs
describe the major design types.
Model DCD drives are general-purpose models furnished
with NEMA standard motors. The last four digits of the
model number designate the speed range and other
design characteristics as listed in the rating tables,
marked on the nameplate or described in other
documentation provided for specific equipment furnished
for an individual customer order.
Typical Dynamatic DCD Adjustable Speed Drive
Figure 2-1