Magnetic Spa - High performance motors

These asynchronous motors have been specially engineered to achieve dimensions of dc motors of similar power and to be suitable for high performance, flux vector type controllers in variable speed applications. The distinctive electromagnetic and mechanical design permits operation in constant power mode at maximum speeds of up to 8000 RPM. The efficient stator cooling system uses an auxiliary electrofan to combine the benefits of reduced dimensions and high, continuous, low-speed torque capability.

The main characteristics are:

• three-phase, 4 pole star winding with no access to neutral
• squirrel-cage rotor
• construction with low losses laminated sheet
• square form, compact
• high, top speed capability
• thermal protection by thermostat embedded in stator winding
• high overload capability
• degrees of protection IP54 and IP23
• insulation class F (CEI EN60034-1)

MA motors are manufactured in fully accordance with standard CEI EN 60034-1 and they comply with IEC 34-1, therefore in according with the rules of the principal European countries.

The whole series is dimensioned in F class; during CEI S1 service the max. overtemperature allowed is therefore 105°C. Notwithstanding this, in order to increase the machine reliability, almost all the insulating materials are in class H (Δt max 125°C, absolute max. foreseen temperature 180°C).

The impregnation is always double and made under vacuum to guarantee the resin penetration. The winding is made of copper foreseen with special enamel to resist to the peaks generated by the inverter (high voltage variations, dv/dt).

In any case it is advisable to contain the PWM frequency and to check that there are no refraction phenomenons on very long power supply cables (high voltage peaks and dv/dt) considering the opportunity of using suitable solutions (for example to insert filters or chokes between inverter output and motor armature).

It is realized through a normally closed contact heat protector with the following characteristics:

Alternatively it is possible to foresee the following types of sensors:

• thermistor PTC type SNM130ES520: nominal resistance 20÷550 Ω that increases considerably ≥ 1330 ø near the temperature threshold 130°C. We advice you a voltage 2.5 Vdc.
• PT100 type 41SRPE06: sensitive element made of platinum that changes proportionally its resistance according to the temperature increasing, at the temperature of 0°C the resistance is 100 Ω. The connection is foreseen with 3 terminals to notice the voltage drop on one line, temperature range from –100°C up to +200°C.
• KTY84-130: resistance that changes proportionally its value according to the temperature increasing, at the temperature of 0°C the resistance is 493 Ω.