**4.2 Kart electric motor**

For this second studied case, we use the same motor structure, but considering a much higher power, adapted to the motorisation of a small sport vehicle, a kart for example.

The simplified specifications of the motor are as follows:


The following **Table 4** summarises the characteristics of the motor designed for this specification. The laminations are identical to those of the previous case (electric boat Section 4.1).

This sizing case is extreme, because, given the power, we are at the limit of feasibility at VLV, especially if we consider the phase current reaching 500 A. However, contrary to the previous case, the maximum power is transient because the speed of a small sport car is very variable on a winding track, the thermal steady state depends on the nature of the latter.

Even though the efficiency remains good, the losses at maximum power are high, more than 2 kW, but in this vehicle the motor is located outside and will be naturally cooled by a large amount of air flow (**Figure 17**). The maximum speed of the vehicle


### **Table 4.**

*Characteristics of the electric kart motor.*

**Figure 17.** *Electric kart.*

is well above 100 km/h, a natural convection cooling is sufficient. Furthermore, the heat exchange is improved by the very low copper to iron thermal resistance.
