Diesel Version 5:Dynamic Brakes
Most modern diesel locomotives have dynamic brakes which slow the train down be converting the kinect energy into thermal energy. This works by turning the traction motor into a generator and creating electricity. That Electricity is then run through a large bank of resistors which turns the electricity into heat. To expel the heat large vans are turned on to cool the resistor banks, the fans are the high pitched whine you hear while the decoders dynamic brakes are active. Dynamic brakes are usually used to maintain train speed while going downhill and cannot slow a train as quickly as train brakes (brake shoes) can. By using dynamic brakes instead of the train brakes railroad maintenance costs are reduced as the brake shoes last longer. Due to the physics of generators when the train reaches low speeds the available braking force becomes negligent and has little impact on train speed.
By default button 5 turns on the dynamic brakes. When button 5 is pressed the prime mover will go to the Dynamic Brake Notch and the fans will spool up to cool the resistor bank.
Press button 5 again and the prime mover will notch up another notch, the fans will increase in intensity, and the prime mover will decelerate a few steps as defined in Dynamic Brake Speed Decrement at the Dynamic Brake Deceleration Rate.
Press the dynamic brake button a third time and the prime mover will notch up final time, the fans will increase speed to their maximum speed, and the train will decelerate a little more.
Additional presses of the dynamic brake button will cause the train to continue to decelerate until it reaches its Dynamic Brake Min Speed, this simulates dynamic brakes limited braking power at low speeds.
Contents
Dynamic Brake Min. Speed
| Dynamic Brake Min. Speed | |
|---|---|
| Range of Values | 0-126 |
| Default Value | 10 |
NMRA CV 189 - Dynamic Brake Min. Speed
Since Dynamic Brakes lose braking power at low speed this CV can be used to simulate that. The locomotive won't go below the speed (0-126) in this CV when the dynamic brakes are applied.
See Also
Dynamic Brake Deceleration Rate
| Dynamic Brake Decel. Rate | |
|---|---|
| Range of Values | 0-126 |
| Default Value | 125 |
NMRA CV 190 - Dynamic Brake Deceleration Rate
The train will decelerate at this rate when the Dynamic brakes are applied. The rate of deceleration is determined the same as as is done in CV3 (the higher the number the slower it decelerates)
See Also
Dynamic Brake Speed Decrement
| Dynamic Brake Speed Decrement Amount | |
|---|---|
| Range of Values | 0-126 |
| Default Value | 5 |
NMRA CV 191 - Dynamic Brake Speed Decrement Amount
This CV controls how many speeds steps the train will slow down per press of the dynamic brake button. The lowest speed is limited by the Dynamic Brake Min Speed
See Also
