With this design the stator is machined and then potted in a cooling jacket under vacuum. The e+a vacuum potting method ensures optimum thermal conductivity between the potting and the cooling jacket so that losses converted to heat can be dissipated discreetly. The cooling jacket can be provided by the customer or developed and manufactured by e+a for the individual application.

The direct potting of the stator in the cooling jacket can be provided for synchronous and asynchronous stators in all sizes.

Stators in standard design are made of a vacuum impregnated winding. They consist of the following main features :




High electrical insulation
High life expectancy
Good value for money

Rotors with squirrel cage in aluminium die-cast are an inexpensive solution. They are light and have a long life expectancy. Maximum circumferential speed is around 130m/s.

Copper rotors distinguish themselves with a considerable higher rotor bore and less additional losses than aluminium rotors. Maximum circumferential speed is around 100m/s. In our special configuration with a reinforcement of the short-circuit rings they can turn up to 170m/s.

e+a offers its own series of high-pole asynchronous machines with special copper rotors for applications requiring high torque and a wide speed range. These motors are used in the machining of titanium for example. They are characterised by high torques at low speeds for a simultaneously large field weakening range.
In comparison to permanent magnet synchronous machines, these motors can accept a higher thermal load and are second to none in utilising torque. In contrast to most applications with synchronous motors a voltage protection module is not required.

Synchronous motor elements

Synchronous motor elements with permanent magnet rotors are a powerful drive for your spindle. They can achieve extremely high torques and maximum speeds (up to 250,000 min-1). These products are characterised by large rotor bores, low rotor temperatures, maximum power densities and extremely short starting times. The rotors can be installed quickly without prior thermally treatment of the rotor or shaft before.

e+a synchronous motor elements can be operated at all standard converter systems that are suitable for the operation of PM motors. e+a offers advice on the individual design of the overall drive system in order optimise the operating characteristics. PM rotors can be removed and reused.

Synchronous motor elements are available
as 2, 4, 6 and 8-pole models
with ENCA™ or ALKA™-type construction for the best possible winding protection
with finished dimensions

Competitive and extremely effective winding protection for small stators.
The ENCA™ winding construction provides an extremely high degree of electrical insulation and maximum protection from partial discharging effects.

ENCA™ winding protection is available for synchronous and asynchronous stators with external diameters of up to 90 mm. All stators up to an external diameter of 240 mm can be supplied with a pre-finished outside diameter.

optimum protection against moisture and grinding dust improved protection against
mechanical damage improved heat dissipation
precise positioning of lead ends

In addition to the technical features of the ENCA™ winding protection, such as longer service life, best possible electrical insulation and optimum protection against moisture, grinding dust and mechanical damage, the ENCA™-V-type construction increases the contact surface between cooling jacket and stator element. As a result of this, special cooling systems can be deployed that require a continuous outside diameter along the entire length of the stator for reasons to do with sealing.

The dimensions of the potting can be determined on a case-by-case basis. The ENCA™ model is recommended as a standard potting variant because of the temperature-independent dimensional stability and the simpler finishing of the stator outside diameter.

e+a stator elements can be supplied with a pre-finished outside diameter on request.

In addition to the benefits of the ENCA™ winding protection (such as a long service life, extremely high electrical insulation and optimum protection from moisture, grinding dust and mechanical damage), ALKA™ winding protection also guarantees optimum cooling of the winding overhangs.

ALKA™ winding protection is available for synchronous and asynchronous stators with external diameters of up to 106 mm. All stators up to an external diameter of 300 mm can be supplied with a pre-finished outside diameter

increased performance due to best possible cooling of winding heads optimum protection against mechanical damage during transportation and installation precise positioning of lead ends
optimum protection against moisture and grinding dust

With this design the stator is machined and then potted in a cooling jacket under vacuum. The e+a vacuum potting method ensures optimum thermal conductivity between the potting and the cooling jacket so that losses converted to heat can be dissipated discreetly. The cooling jacket can be provided by the customer or developed and manufactured by e+a for the individual application.

The direct potting of the stator in the cooling jacket can be provided for synchronous and asynchronous stators in all sizes.

Because of their large rotor bore and their low weight, e+a permanent magnet rotors with carbon-fibre reinforced plastic (CFRP) sleeve provide a very rigid drive train made up of shaft and rotor. With the tapered sleeve system, the rotor element is supplied as a complete system and is attached to the customer-supplied shaft by a simple fitting procedure. e+a uses a special composite consisting of resin and carbon fibres developed specifically for high temperature strain loads. The maximum permissible temperature can be adjusted on request to meet customer specifications. e+a developed its own procedure for the construction of the CFRP sleeves to allow maximum flexibility in the design of the sleeve. As a result, rotor elements with exceptionally high power densities and circumferential speeds can be manufactured.

This rotor system also lends itself especially well to situations where magnets are not to be attached directly to the shaft for logistical reasons. This may be the case if the customer does not wish to ship shafts and fit magnets by himself to the shaft at the same time.

The thermal resistance of the CFRP wrap is suitable for normal spindle drive applications. Special instructions must be followed when dealing with rotors.

With the direct assembly method, the magnets and the CFRP sleeve are fitted directly to the customer-supplied shaft. This allows for a bigger shaft diameter compared to the tapered sleeve system. Apart from that, the same technical boundary conditions can be provided in both permanent magnet rotor systems in relation to power density, circumferential speed and ambient temperature.

The rotor position measuring device ensures that the same commutation angle is always produced with spindles of the same construction type during the installation of the e+a synchronous rotor. This dispenses with the need for individual programming of the commutation angle at the frequency inverter. When a spindle is replaced the drive can be monitored at all times and is therefore protected from being damaged beyond repair.

The motor must be mechanically driven in order to carry out a measurement. The measured values are easily read out using the RS232 interface in conjunction with measurement report software.

Measured values
Speed, voltage constant, voltage (phase-phase), mechanical angle, electrical angle, number of poles, number of sensor teeth

Cable connections
Motor phase U, V, W; sensor: 5VDC, 1VSS, A/B/R; serial interface RS232

Options
Sensor cable, case