PicoScope EV Testing and the Milli Ohm Motor Tester

Steve Smith introduces the MT03A Milli-Ohm and Electric Motor Tester. This remarkable tool allows you to measure extremely low resistances and test motors. Steve takes us through concepts and testing a motor from a Toyota Hybrid Vehicle.

A multimeter is useful above 1 ohm. The milliohm meter works for resistance below 1 ohm.

Having found the problem, Steve also performs an insulation test using the Pico Insulation Tester - enjoy the fireworks!

Running Time 26 min 46 sec

Toyota Hybrid Motor Testing Continued

A new YouTube Video. Steve performs a quick balance test on the Toyota Hybrid Motor. He then tests the resistance of a bus-bar and shows the effect of loosening a connecting bolt, even slightly.

I * R = V. At 100 A, an increase of 10 milliohms produces a 1 V drop. Think of the effect at 800 A, a reasonable starter motor current. The voltage drop would be 8 V, enough to prevent most vehicles from starting! Also, consider the power that would be dissipated. V * I = P, 1 V * 800 A = 800 W, enough to produce lots of heat at the connection.

PicoScope EV Diagnostics - Renault Zoe Type 2 charging error

Is it a car or charger fault? Steve Smith investigates a charging error on a Renault Zoe. The Charger-vehicle proximity line resistance (Type 2) Guided Test is consulted. Again, various techniques are discussed, including using a resistance lead, a differential probe, safety considerations and how to manually test and engage the lock pin.

Steve also found and discussed a charger anomaly in that it emitted a PWM signal even though it was not connected to the vehicle.

Terminology:

CP means Control Pilot which provides bidirectional communications between the electric vehicle and the charging system. This checks the maximum amount of current that the EV is able to take at any one time.
PP means Proximity Pilot which tells the charging equipment what type of cable is connected to the socket. Different cable thicknesses can carry different amounts of electrical current.

When to use the 2-Pole Voltage Detector

Steve Smith discusses common errors when using a multimeter. You could inadvertently mis-configure your multimeter and think the system is safe.

Steve shows us why the Two-pole Voltage detector is such a handy tool to make sure that you have safe conditions when you work on high-voltage systems.