Published On Feb 16, 2021
Join me for a deep dive into the details of the 18,000 RPM performance rear motor and drive unit from a 2015-2016 Tesla Model S P90D. This drive unit is similar to the one used in the 2017-2020 P100D. The video is divided into four sections showing: 1. The motor and gears. 2. The high-performance bearings. 3. The lubrication system. and 4. The cooling system.
Thank you to everyone for catching my errors. There are always errors ;)
1. The Nissan Leaf ring gear is held on with 8 bolts, not 6.
2. The fluid in this drive unit is Dexron 6 transmission fluid.
3. Induction motor rotors do not have poles, just the stator. The 60 slot stator has four poles.
4. Silicon Nitride is a ceramic material.
1:35 Gearbox housing
2:10 Video Section 1 - Gears and Motor Rotor
2:45 The giant differential ring gear with 16-bolts!
4:20 The giant differential case bearings
4:50 The differential case speed at 250 km/h (155 mph) = 1841 RPM
5:15 MUST SEE Comparing the Tesla 213mm x 50mm. ring gear to a Chevrolet Bolt EV and Nissan Leaf EV
5:40 A Chevrolet Bolt EV differential 198mm x 34.3mm ring gear with 12-bolts.
6:10 A Nissan Leaf EV differential 200mm x 32mm ring gear with 8-bolts!
7:30 The Counter Shaft (Jack Shaft) with 25 pinion gear teeth. 78/25 = 3.12:1 Gear ratio from countershaft to the differential case
8:50 The countershaft speed at 250 km/h (155 mph) = 5743 RPM
9:30 The motor shaft with 25 teeth drives 78 teeth on the countershaft for another gear reduction of 78/25 = 3.12:1
10:08 The motor shaft speed at 250 km/h (155 mph) = 17,919 RPM
11:20 See all three gears in the reduction gearbox with an overall gear reduction of (78/25) x (78/25) = 9.7344:1
12:05 MUST SEE The AC Induction Motor Rotor with 74 bars
13:25 Motor specifications for power, torque, and gear ratio
15:00 MUST SEE Ceramic Bearings (Silicon Nitride) on the rotor from the SKF Group (skf.com)
16:22 MUST SEE Close up view of silicon nitride bearing
18:20 The motor rotor speed sensor reluctor wheel (tone ring)
19:22 Must SEE The rotor installed on the drive gear and the functioning gearbox
20:18 Video Section 2 - Specialized Bearings
21:21 The 60 slot four-pole stator and housing
23:05 The oil pump and how it is overdriven by the differential ring gear 23/78 = 0.2948:1 gear ratio (3.339 times faster than the ring gear)
23:55 MUST SEE The function of the oil pump (it may surprise you)
26:27 Motor shaft bearing reference speed and limiting speeds
27:30 How to run bearings at higher speeds than their limiting speeds
29:54 Video Section 3 - Lubrication
30:25 Drain and fill plug locations
30:50 Gearbox vent and inverter vents
31:05 Sport model label
31:39 MUST SEE Four different sealed areas in the drive unit
32:46 Video Section 4 - Cooling System
33:30 MUST SEE The coolant inlet port and the two paths coolant takes
33:53 Up for rotor cooling and gearbox cooling
35:03 Down for stator and inverter cooling
36:05 Coolant from the rotor moves to the gearbox heat exchanger and the outlet port
37:25 Stator temperature sensors
38:10 Coolant from the stator to the inverter coolant passages
38:28 Stator coolant temperature sensor
38:35 MUST SEE Insulated-Gate Bi-Polar Transistor (IGBT) module coolant passages and flow through gearbox passages
40:34 Inverter coolant outlet temperature sensor
40:45 The gearbox oil-to-coolant heat exchanger
41:38 Coolant outlet port to coolant pump and on-board charger module under the back seat.
41:55 Drive unit cooling system summary
43:04 IGBT inverter modules installed and inverter cover
43:40 High voltage battery cable connections and low voltage connections at the inverter
44:35 Video summary
Weber State University (WSU) Davis Campus - Automotive Technology Department - Advanced Vehicles Lab. A technical description and demonstration of the Tesla P90D Rear Drive Unit (RDU). We teach current vehicle technologies to our automotive students at Weber State University and online. For more information visit: http://www.weber.edu/automotive
This video was created and edited by Professor John D. Kelly at WSU. For a full biography, see http://www.weber.edu/automotive/J_Kelly.html
Visit my other youtube channel https://www.youtube.com/user/vibratesoftware to see the amazing NVH app for vibration diagnosis!
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