English
Français
Türkçe
Español
Русский
With a 132 kW three-phase asynchronous electric motor, the real work begins after the motor has been chosen: if the cable, switchgear and transformer capacity feeding a load that draws roughly 220–230 A rated current on a 400 V supply are not planned correctly, even the most suitable motor will cause trouble at its first start. All three 132 kW models in the HEM Motor 2026 catalog use a 315 frame and have a 400/690 V (Δ/Y) winding; therefore the decisions on the panel side depend less on speed and more on the starting method and the length of the line. This article explains which information should be given to the electrical design before ordering a 132 kW (180 HP) motor.
Current and torque values of the 132 kW models
The input for the panel calculation is the motor nameplate. The values below are taken from HEM Motor product records; all three models have a cast iron frame, IP55 protection, class F insulation and are rated for 50 Hz.
| Model | Poles / synchronous speed | Rated speed | IEC frame | Rated current (400 V) | Rated torque |
|---|---|---|---|---|---|
| 315L2-6 | 6 poles / 1,000 rpm | 988 rpm | 315L | 232 A | 1,276 Nm |
| 315M-4 | 4 poles / 1,500 rpm | 1,488 rpm | 315M | 224 A | 847.2 Nm |
| 315M-2 | 2 poles / 3,000 rpm | 2,978 rpm | 315M | 222 A | 423.3 Nm |
The striking point is this: the current is very similar at all three speeds, while torque changes in inverse proportion to speed. So in terms of cable and contactor size there is no marked difference between the 2-pole and the 6-pole motor; the difference appears in how much torque the machine demands from the motor at start-up. For the current values of other ratings, see our electric motor current table.
Who calculates the cable size, and with what information?
We do not give the cable cross-section of a 132 kW motor as a number in this article, because even at the same current the correct size changes from site to site. The cross-section is determined by the electrical engineer or panel engineer designing the project, according to the applicable installation rules. To do that calculation, they need the following information in full:
- Rated current and voltage: The 400 V current on the motor nameplate (e.g. 224 A for the 315M-4) and the connection in which the motor will run.
- Line length: Cable length from the panel to the motor. On long runs, the cross-section is often decided not by current-carrying capacity but by the voltage drop during starting.
- Installation method: Cable trunking, tray, underground or conduit; how many circuits run side by side. Grouped cables heat each other.
- Ambient temperature: Hot routes such as a boiler room, roof space or a tray exposed to the sun.
- Conductor material: Copper or aluminium.
- Starting method: Direct-on-line, star-delta, soft starter or frequency inverter. This choice also changes how many cores go to the motor.
With star-delta starting, two separate three-core lines are usually run from the panel to the motor, and the six terminals in the terminal box are connected individually. The current in these lines is the phase current flowing through the winding; it is about 1/√3 (≈ 58%) of the line current. This general rule affects how each of the two lines is sized; leave the calculation to your engineer, but state from the outset that a six-terminal connection will be used.
Starting current, transformer and supply capacity
An asynchronous motor started direct-on-line draws several times its rated current at the first instant. The starting current ratio (Ia/In) valid for the model should be read from the nameplate and catalog data. In the 132 kW class, this sudden load can pull down the voltage of a small transformer for a few seconds; contactors of other machines fed from the same transformer may drop out and lighting may flicker.
To get a rough sense of scale, let us do a hypothetical calculation: if the 315M-4 draws 224 A at 400 V at full load, its apparent power is about √3 × 400 V × 224 A ≈ 155 kVA. This is only the load in continuous operation; at start-up, a demand several times larger is briefly placed on the transformer. The starting method should be chosen by evaluating the transformer rating, its short-circuit impedance and the other loads in the plant together. This assessment is made by an electrical engineer who knows the supply side; our contribution as the motor supplier is to provide the correct nameplate data.
How starting options affect the panel
Because the winding of the 132 kW models is 400/690 V (Δ/Y), the motor runs delta-connected on a 400 V supply. This allows star-delta starting: in the star connection at start-up, both current and torque fall to about one third compared with direct-on-line starting. The differences between the options from the panel's point of view are roughly as follows:
- Star-delta: Three contactors and a timer relay, six-core supply to the motor. Common on fans and centrifugal pumps that start with a light load. On a machine that starts under heavy load, the low torque in star may not be enough.
- Soft starter: Raises the voltage along a ramp and limits the starting current in an adjustable way. A single three-core line goes to the motor. In most applications a bypass contactor is used after starting.
- Frequency inverter: Can keep the starting current around the rated current and provides speed adjustment. Our three-phase series are suitable for speed control with a frequency inverter; for prolonged full-torque operation at low speed an external fan may be needed, and if the cable between drive and motor is long a dv/dt or sine filter is considered; these conditions are stated in the order.
With drive supply, the motor cable is usually screened, and the screen must be correctly earthed at both ends. If the line length approaches the limits given by the drive manufacturer, the filter decision should be made at the panel stage. If you want to compare 132 kW motor options, review suitable HEM Motor models and current prices in our store.
