Free Red Seal Trade Simulators: Hydraulics and DC Circuits

Each simulator is a simplified teaching model of one system. It is not a real machine and not a service or repair procedure, so the readings are relative or example values. Use it to see what a test should show, then practise exam questions for your trade.

The simulators

421A Closed-Loop Hydrostatic Drive Simulator Run a generic closed-loop hydrostatic drive in neutral, forward, reverse and stall, then find 5 drive faults from relative gauge and flow readings at the test ports. Open the hydrostatic drive simulator → 421A · 310T · 310S · 309A · 442A DC Circuit Fault Simulator Put a virtual meter on an example 12 V lamp circuit, and on a 24 V view with two 12 V batteries in series, then find opens, shorts and high-resistance connections in 8 fault scenarios. Open the DC circuit simulator →

What each one covers

Hydrostatic drive simulator

Modes: Explore, Drive, Find the fault

What each line and valve in the drive does
Drive operation in neutral, forward and reverse, and charge pump circuits
Finding a drive fault from loop, charge and servo pressures, and from charge pump and motor case drain flow

DC circuit fault simulator

Modes: Explore, Meter, Find the fault

Voltage and resistance readings between test points
Voltage-drop testing across a switch, a connector and the battery cables
Telling an open from a short to ground or a high-resistance connection

Which simulator for your trade

Trade	Simulator
421A Heavy Duty Equipment Technician	Hydrostatic drive, DC circuit
310T Truck and Transport Mechanic	DC circuit
310S Automotive Service Technician	DC circuit
309A Construction Electrician	DC circuit
442A Industrial Electrician	DC circuit

The hydrostatic drive simulator is built for 421A. Other trades that service mobile equipment hydraulics can use it too.

How to get the most from them

Explore first. Tap each part of the drawing to read what it does before you change anything.
Take readings on the healthy system. Knowing the normal reading is what makes a wrong one stand out.
Then pick a fault. Read the symptom, take the readings, and choose a cause. If the readings do not point to one cause yet, take more before you choose.
Finish with questions. Each simulator links to free practice questions on the same topic for your trade.

More practice: all free practice quizzes, or the guide to every Red Seal trade.