Why EC

Permanent-magnet motor and integrated control for variable-speed duty.

Comparing an EC (electronically commutated) PM synchronous motor with a fixed-frequency induction motor, the legacy site claimed "20% smaller, over 30% lighter than an induction motor of the same rating" — comparison figures with no reference model and no test condition, so they are not used here. Only three differences actually matter for ventilation equipment.

EC motor flange end and integrated controller

W-02Comparison

Three system differences for variable-speed ventilation

Qualitative, with no percentages. Each of the three is noticeable in how ventilation equipment actually runs, without instruments.

01Torque at low speed

Fixed-frequency induction

A fixed-frequency induction system does not provide continuous speed control. With a VFD it can maintain torque over a defined range, while continuous low-speed capability still depends on motor cooling, drive control and thermal limits.

With suitable control, a PM synchronous system can cover low-speed operating points; the usable torque range still requires controller and thermal-limit data.

02Speed control

Fixed-frequency induction

A fixed-frequency scheme can only switch units on and off, leaving intermediate points unreachable; adding a VFD means another cabinet and more wiring.

The controller sits on the motor; RS485 or a 0–10 V reference gives continuous speed control directly.

03System makeup

Fixed-frequency induction

Motor, drive and cabinet are three items, with a power cable run and a set of terminals between cabinet and machine.

Motor and controller are one unit: one external wiring run and one separate cabinet fewer — which matters most where servicing is hard, such as roof units.

W-03Operating range

Actual operating limits require test data

T = 9550·P/n only converts one power–speed point into theoretical torque. The real torque–speed envelope also depends on continuous and peak current, voltage, control strategy and thermal limits; without them, the site shows one calculation point and no curve.

Power–speed calculation referenceEC80 Domestic

T = 9550 · P / n

The formula applies only to one paired operating point. Extremes from separate power and speed ranges cannot be combined; a real envelope requires controller limits, thermal limits and test data.

Drive chain and system boundarySolid outline = Rasta scope

Controller and motor ship in one housing; the customer side needs only power and a single control signal. The RS485 register map and 0–10 V mapping are pending from the factory.

The third difference is drawn here too: controller and motor share one housing, so the customer-side interface is power plus one control signal. A fixed-frequency plus VFD scheme would add a cabinet node and a power cable run to this diagram.

W-04Specification basis

Comparative data requires defined models and test conditions

Withdrawn is not the same as denied; the documents are missing. With a reference model, test conditions and a report, these can be said again — and said more firmly.

D20% smaller than a PM motor of the same ratingNo reference model or measurement method, and the comparison object is a generic "other PM motors"
DOver 30% lighter than an induction motor of the same ratingNo reference product model, structural dimensions or weighing condition
DMeets IE5 efficiency classThe same sentence appears on all five versions with no test report locally
D10–30% / 20–50% energy savingFrom legacy articles, with no verifiable project report or measurement baseline

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