INDUSTART starters work on principle of impedance change of specially produced 3ph- inductor with iron core because of rotor frequency change. Matching with rotor parameters of given motor is done by selection of operation inductor's tapping by commissioning. This tapping allows changing impedance in the range from 15 up to 100%. Advantages of INDUSTART in comparison with normal resistant starter are high thermal capacity, dimensions and weight, high reliability and durability because of contact's problems elimination. The starter includes only one contactor that is after start time short-circuited.

TYP MA - basic design

The starter is delivered in a switchboard case with enclosure IP54 with all devices and equipment that includes short-circuit contactor, time relay, thermal protection, light signalization (starting, running, fault) and auxiliary contacts for remote control. Control voltage 230 V 50 Hz.

Technical Data:

Type: MA 30 B MA 45 MA 90 MA 125
*Max. power: 37 kW 55 kW 110 kW 155 kW
*Number of starts/hour h: 9 7 6 7
*Number of starts one after another z: 4 4 4 5
Max. rotor current [ A ]: 140 275 425 525
**Max. rotor voltage [ V ]: 600 600 800 800
***Max. rotor voltage [ V ]: 500 500 550 600
Dimensions [ mm ] - height: 1200 1200 1200 1600
Dimensions [ mm ] - width: 800 800 800 800
Dimensions [ mm ] - depth: 400 400 400 400
Weight [ kg ]: 80 105 120 140
Type: MA 175 MA 350 MA 500 MA 1000
*Max. power: 200 kW 400 kW 710 kW 1000 kW
*Number of starts. h: 5 4 4 4
*Number of starts one after another z: 4 4 4 4
Max. rotor current [ A ]: 625 1100 1600 2000
**Max. rotor voltage [ V ]: 1000 1200 1200 1200
***Max. rotor voltage [ V ]: 750 900 900 900
Dimensions [ mm ] - Height: 1600 1600 2000 2000
Dimensions [ mm ] - Width : 800 800 1600 2200
Dimensions [ mm ] - Depth : 400 600 600 600
Weight [ kg ]: 150 280 470 900

*For the start volume (f = 1.4) and starting time 15s in switchboard with IP55.
** For normal start. Short-circuit starter's contactor is dimensioned according to real value of rotor voltage U20.
*** For braking and reverse

INDUSTART MA 500 is installed to two switchboard cases.


Function Principle

INDUSTART starters work on the external eddy armature base that is connected through slips to the rotor circuits. Eddy armature is made of special produced 3ph inductor with iron core with specific shape and parameters. As the frequency goes down during the motor starting, the inductance (impedance) of the inductor goes down as well. This continuous impedance change modifies moment characteristic of the typical slip ring armature asynchronous motor to the moment characteristic of the asynchronous motor with eddy armature. Motor is starting more continuously, without any "jumps" that are common for resistor starters. The effect of that is elimination of electrical stress in motor's winding, in the network and mechanical stress of the whole drive.

Fundamental requirement for such an eddy armature is high quality winding's thermal isolation of the inductor against iron core, that is strongly heated during starting. INDUSTART advantages against other starters are its high thermal capacity, dimensions and weight as you can see from the table. Furthermore INDUSTART does not need any special liquid and minimizing the number of contactors. In standard design it includes only one contactor that is after start time short-circuited. This brings high starter reliability.


The starter is based on special designed and produced inductor with iron core. The winding is thermally isolated against the iron that is heated during the staring. At critical points of the winding are installed thermal detectors that initialize drive's turning-off when critical point is achieved.

For more equivalent drives with smaller number of starting can be nonstandard design ordered that allows using one starter for two or more drives.

Standard starter design is in cases Spálovský , coverage IP54 with installation of all devices and equipment that includes short-circuit contactor, time relay, thermal protection, light signalization (starting, running, fault) and auxiliary contacts for remote control. Control voltage 220 V, 50 Hz.

It can be delivered in built in design with accessories for installation into the customer's switchboard case. The customer has to respect minimal recommended switchboard case's dimension and its position. The switchboard case does not have extra ventilation. It has to be taken into consideration that a distance between inductor's winding and the starter's front part should be large enough to make air circulation possible.

Last but not least advantage of the INDUSTART is that it does not contain any moveable parts, any liquids and this all make of it reliable and high quality starter even for extreme running conditions.

Thermal Protection

Starters are equipped by thermal detector KLIXON with contact that is in normal position closed. The detector is brought out at the lower part of the desk where inductor's tapping points are also brought out. Starters in the box design have this contact already connected to the auxiliary circuit according to scheme that is delivered with all documentation.

The contact of the thermal detector is connected to the auxiliary control circuit in such a way that it opens (motor's starting break down) when the contact opens during adjusted time of the time relay. It can happen that it opens because of thermal inertia after the starting time and closure the rotor's contactor. This problem is solved by auxiliary contact of rotor's contactor and after the contactor closure is the indicator's contact short-circuited by this auxiliary contact. Thermal indicator protects the starter against burning because of running faults or incorrect manipulation.

When starting up conditions are extremely bad (starting time, number of starts), the starter's thermal capacity can be increased by adding extra ventilation.


INDUSTART starter are convenient for starting up of asynchronous slip-ring motors for pumps, ventilators, band conveyers, cranes, kneading machines, pressing machine, centrifugal machines and bruising mills drives. They can be also used for:

  • High inertia moment
  • Short and repeating starting ups
  • Substitution for present liquid starters

For such applications the same starter design and impedance is used as for normal starting up. When the motor is again started and it is still rotating because of inertia, residual rotation does not play any role and the starter reaches automatically the same torque that corresponds to the motor's power, adjusted impedance and instantaneous motor's speed. For this application is necessary to think about function and adjustment of the time relay or adding blocking mode to the control circuit to prevent closure of the rotor's contactor during restart.

  • reverse mode

INDUSTART can be run in reverse mode by connecting reverse contactor into the stator's circuit. The same impedance as for normal mode is used. The rotor's contactor (time relay) has to be blocked to prevent closure during starting up or braking. Torque in reverse mode corresponds at least to torque in normal mode.

  • Starting up inductor for decreasing the stator current LV asynchronous motors with short-circuit armature