Program 2011/2012 - maxon motor - #29

Sinusoidal commutation

Sinusoidal commutation for EC motors with

slotted winding is basically possible, provided

that an encoder can be mounted. The main

benefit of sinusoidal commutation - the smooth

operation - only comes into play to a limited

degree due to the detent.

Integrated electronics

For motors with integrated electronics, the

electronic commutation (mostly block com-

mutation with Hall sensors) is built in. A speed

controller and other functionalities can also be

implemented.

Features

- Simple operation with DC voltage

- Fewer connections than with the EC motor

- No additional electronics required

- Output power reductions possible due to less

space for power electronics

Hall sensor circuit

The open collector output of Hall sensors does

not normally have its own pull-up resistance, as

this is integral in maxon controllers. Any excep-

tions are specifically mentioned in the relevant

motor data sheets.

Wiring diagram for Hall sensors

' > Hall sensorsupply voltage

Control

circuit

Winding arrangement

The winding is divided into 3 partial windings

which have several stator teeth each. The

partial windings can be connected in two

different manners - "Y" or "A". This changes

the speed and torque inversely proportional

by the factor /3.

However, the winding arrangement does not

play a decisive role in the selection of the

motor. It is important that the motor-specific

parameters (speed and torque constants) are

line with requirements. Flat motors and EC-i are

normally "Y"-circuited.

"Y-circuit" "A-circuit"

U2-3 1)2-3

The maximum permissible winding temperature

is 125°C. (EC-i 155°C).

For further explanations, please see page 137

or "The selection of high-precision microdrives"

by Dr. Urs Kafader.

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May 2011 edition / subject to change Technology - short and to the point 29