ZF’s new 200 kW electric drive is a quarter smaller and needs half as much magnet material

Higher speeds allow a smaller motor

The High Revolution Drive combines an electric motor, inverter and reduction gearbox in a compact three-in-one drive unit.

Engineers increased the motor’s maximum speed to 30,000 rpm, while a comparable ZF SELECT drive operates at up to 18,000 rpm.

The solution is based on simple physics: at the same power output, higher rotational speed means less torque is required. This allows the motor’s rotor to be made smaller and lighter.

A two-stage reduction gearbox uses a ratio of approximately 18:1 to convert the motor’s high rotational speed into the tractive force needed at the wheels. The drive presented delivers 200 kW of peak power and up to 3,500 Nm of torque at the wheels. It is important here to distinguish between motor torque and wheel torque. The 3,500 Nm figure is not the electric motor’s own torque output, but the value delivered to the wheels through the reduction gearbox.

Magnet requirements cut in half

Compared with a SELECT drive of the same power output, the new system requires nearly 25% less installation space and weighs almost a quarter less.

Even more important is the 50% reduction in the amount of magnet material.

The rare-earth metals used in permanent-magnet electric motors make production dependent on complex international supply chains. Lower magnet requirements help reduce both material costs and supply-chain dependence.

ZF’s solution does not, however, dispense with magnets entirely.

High rotational speeds also place greater demands on bearings, gears and vibration damping. ZF developed the motor, reduction gearbox and power electronics as an integrated system to keep noise levels under control.

The result is efficiency of around 93%, matching the figure for the company’s conventional SELECT drive.

This means ZF has achieved a significant reduction in size and weight without sacrificing the efficiency of the comparable drive.

A smaller drive gives carmakers more flexibility

The High Revolution Drive is aimed at high-volume electric cars with drive power of approximately 150–200 kW.

The system is compatible with both 400- and 800-volt electrical architectures and uses components from ZF’s existing SELECT platform.

For European carmakers, the more compact drive offers an opportunity to reduce vehicle weight or use the freed-up space for batteries, the passenger compartment and other components.

However, a drive that is a quarter smaller should not be confused with an equivalent increase in range. The electric motor and reduction gearbox account for a relatively small share of a car’s total weight, so the actual energy savings depend on the vehicle’s overall design.

ZF’s approach also differs from those of its competitors. While some manufacturers are focusing on magnet-free motors or new semiconductors, ZF is seeking gains through higher rotational speeds and optimisation of the entire drivetrain.

Series production planned by 2030

ZF is already in talks with several carmakers and aims to start production of the High Revolution Drive by 2030 at the latest.

The company has not disclosed the names of its first customers or the price of the new drive.

The real value of ZF’s innovation does not lie in its 200 kW output, as there are already plenty of electric drives offering that level of performance on the market. What matters is achieving the same power with a smaller, lighter design that requires fewer critical materials.

For Europe’s electric car industry, this could be even more important than another power record. Competition with Chinese manufacturers is forcing costs down, and every kilogram of weight and gram of magnet material saved helps move closer to that goal.