FAQ on POWER CAB POWER RATINGS
On this page, we address the following questions:
1) WHAT IS THE POWERCAB TRACK CURRENT RATING?
2) HOW MANY ENGINES CAB MY POWERCAB RUN?
3) HOW CAN I TELL IF MY POWERCAB IS BEING OVERLOADED?
4) WHAT IS THE POWERCAB's MAXIMUM CURRENT RATING?
5) WHAT DO I DO TO ADD MOVE POWER TO THE POWERCAB?
6) CAN I UPGRADE THE POWER CAB WITH A 3A DC POWER SUPPLY INSTEAD?
7) IS THE POWERCAB COMPATIBLE WITH DCC CIRCUIT BREAKERS?
1) WHAT IS THE POWERCAB TRACK CURRENT RATING?
SIMPLE ANSWER: The maximum continuous current rating is the same as the OUTPUT current rating printed on the NCE supplied power supply.
LONG ANSWER: The answer depends on the PowerSupply you connect to it as long as it rated at 3amp or less. See section 4 below for more info.
2) HOW MANY ENGINES CAB MY POWERCAB RUN?
The following rating are based on the use of MODERN motors in the engines and only one motor per engine. Modern motors are typically are fully enclosed motors. Why? Older motors consume a lot more current than modern motors. This is important in understand how many locomotives a DCC system can run.
Signs of an old motor: Any open Frame motor where you can see the motor brushes. "Pittman" motor often sold in old brass.
Engines only consume power of any consequence when the motor is running. Engines sitting still on the track with only background sound and lights on do not consume enough current to worry about. So the better question to ask is:
How many MOVING Engines can I run on my PowerCab?
Simple Answer: If you make some good assumption about the current rating of the motors, then a worse (most conservative) MINIMUM number of engines possible. Assume PowerCab is rated at 1.5Amps*.
N Scale Motor = 0.25A. Maximum engines = 1.5A / 0.25A = 6 Engines.
HO Scale Motor = 0.5A Maximum engines = 1.5A / 0.50A = 3 Engines.
O Scale Motor = 1.0A Maximum engines = 1.5A / 1.00A = 1 Engine. (This requires a modern motor type)
Why Minimum? Because the only time you can draw this much current continuously from the motor is when the train has a full load going upgrade at a high rate of speed and just making it up the hill. In practice nobody does that and as a consequence, the actual motor current needed is far less. In other words, you can typically run a lot more engines (1.5x) than the minimum with no problems. HOWEVER O scale engines will REQUIRE testing to verify they will work due to big variations in motor current from different brands, age and models.
NOTES:
1) The actual CONTINUOUS DC current capacity of the PowerCab is printed on the DC power supply. See Section 4 below for more information.
2) IGNORING POWER LIMITATION, The maximum running trains the PowerCab can control is 12 engines. The Power limitation issue will be reached first.
3) HOW CAN I TELL IF MY POWERCAB IS BEING OVERLOADED?
Two ways to find out.
METHOD 1: Run and test. Run all the trains you plan on running at the same time on the layout that are realistically Manageable. Realistically Manageable? Anyone can run more trains, the question is can you keep them all under control so they never run into each other or crash somehow. As soon as you get going, you will quickly find out if you have enough power and/or have full control. If there is consistently to much power being drawn, the PowerCab itself will shutdown and restart with No harm done. Next: Proceed to the testing section below. This is the only option with O scale.
METHOD2: Measure each engine and calculate. The great thing about the PowerCab is that it can measure the AVERAGE motor/locomotive current FOR YOU and let you see for yourself how much actual current is being used. Not recommended for O scale and larger.
How? Follow these steps.
a) Go to the SET UP THE CAB PARAMETERS menu. Press "ENTER" key.
b) Display will now say: "SHOW TRK CURRENT 1=Y". Press "1" key.
c) Press PROG/ESC key.
The clock display will be temporarily replaced by the current meter display. IF you attempt to do any programming or cycle power, the clock display will be restored and you will have to repeat the above sequence to get the current meter.
(Note: The AVERAGE current is much less than the stall current rating of the motor. In terms of power, the PowerCab protects itself based on the peak/stall current.
TESTING THE LOCOMOTIVE
This test is for a single O scale engine or running multiple engines at the same time in smaller scales.
If you answer yes to any of the questions below, you have a problem.
PREPARING STEPS
1) Remove all other engines not involved in the test from the layout. (Required to fair test of the PowerCab and to get a good accurate current readings)
2) Clean the track (the path the engine(s) will be going around) and wheels of the engine(s).
3) Place the engine(s) on the track connected to a train you plan on running with the engine(s).
PRE TESTING STEPS
With the engine(s) stopped:
4) Check the Headlight. Does the headlight work?
5) If you have sound, also check the horn/whistle work? Does the horn/whistle work?
6) Repeat steps 4 & 5 several times while noting how "fast" and consistent the function control is. Your looking the delay in time between the push the button to the function responding on the locomotive. This will become your Go or NoGo time and consistency reference when you test run the engine.
7) Test the horn/whistle with the headlight on. Does the headlight dim when you play the horn/whistle?
If Yes, this is a sign of poor layout wiring or bad connections. Fix the wiring and then come back and repeat these test.
If No, then proceed to the test steps.
STARTING STEPS
8) With the engine alway starting from a dead stop and accelerating while the headlight is on, does the headlight dim?
RUNNING STEPS
With the engine running at normal speed:
9) Constantly vary the speed of the engine everywhere on the layout. Did you lose speed control?
10) Constantly test the functions that you engine supports everywhere on the layout. Did you lose headlight and/or sound control?
11) With the headlight on, does the headlight dim when you play the horn/whistle?
12) If you have a part of the layout with a grade, then repeat step 10 & 11 above while running the engine at a high speed up the grade.
IF you answer YES to any of the above questions, you locomotive is overloading the PowerCab. See section 5 below.
Only by testing will you will find out your answer. If lose PowerCab power as soon as the engine starts, you instantly know for sure. If you do not have reliable control when running around the layout, then the locomotive is at edge of being to much for the Powercab and the conclusion is the same.
4) WHAT IS THE POWERCAB's MAXIMUM CURRENT RATING?
The NCE manual says:
Power Input Requirements: 10-15V regulated DC, 3A maximum
Power Connector: 5.5mm x 2.5mm center positive
What you need to know.
a) The NCE PowerCab does not regulate the track voltage. The Power-supply does. Hence the DCC track voltage is about the same as the PowerSupply's DC output voltage rating. So get a power supply that is somewhere between 12VDC and 14VDC. A 13.8VDC is a common voltage the emulates a car battery voltage.
b) The NCE PowerCab does not set the current limit. The Power-supply does. Hence the PowerCab current rating is the same as the PowerSupply's current rating. However, if the current exceeds 3Amps, the NCE PowerCab will shutdown to protect itself.
5) WHAT DO I DO TO ADD MOVE POWER TO THE POWERCAB?
NCE official recommendation and best solution is to upgrade the PowerCab system to use a NCE SB3a (now Discontinued) or the new SB5. These are combination Command Stations PLUS 5 Amp booster in a single box. It is the intended power upgrade path for the PowerCab. It will allow your PowerCab to be unplugged and used like any other cab giving you the MISSING walk around capability you desire. You also keep you PowerCab and it associated PCP panel for the programming test bench where it will do the most good as a PowerCab. Win Win solution.
6) CAN I UPGRADE THE POWER CAB WITH A 3A DC POWER SUPPLY INSTEAD? (Using a non NCE Power Supply)
Yes but there are rules and consequences. Failure to follow them can destroy your PowerCab and NOT have it's warrantee honored.
WHAT ARE THE CONCERNS?
1) The PowerCab is NOT DESIGN TO RUN 3AMPS CONTINUOUSLY. The PowerCab can overheat deforming the plastic shell due to the high heat build up. You want the 3amps to ONLY be a peak current to handle high inrush current common found when working with lots of sound engines.
2) The PowerCab long flat cable has small gauge wire. The wires will lose (drop) a lot of voltage at high operating currents and may get warm when running a lot of trains. The more trains you run, the slower they all get or top speed is reduced. The cable and associated telco RJ jacks and plugs are not really designed to support 2Amps of current efficiently. The flat cable will get warm.
REQUIRED PROTECTION
Never run the PowerCab directly connected to the track. You MUST install some protection. Chose one of the following options.
1) Install a 2A slow blow fuse in series between the DC power supply and the DC input jack of the PowerCab.
2) Install a 2A circuit breaker in series between the DC power supply and the DC input jack of the PowerCab. (Not a DCC circuit breaker)
The following are installed between the PowerCab track terminals and the Layout.
3) Install one NCE's CP6 light bulb device (Intended for N scale and can work on small HO).
4) Install one #1156 light bulb between the PowerCab and the layout.
5) Install one DCC circuit breaker set to current that is 2 amps or less. See section 7 below for more information.
6) Install multiple DCC circuit breaker to create multiple power districts with the trip current set to 2 amps or less. See section 7 below for more information.
Best Recommendation: See section 5 above. More power and a better operating experience. WIN WIN.
7) POWERCAB COMPATIBILITY WITH DCC CIRCUIT BREAKERS
There is two parts to answer this question.
1) What Circuit breakers work?
First there is only ONE brand of DCC circuit breaker devices sold that are designed to work specifically with the PowerCab. DCC specialties PSX series of products. NCE only sells the CP6 which is a light bulb based protection which is targeted for N scale.
There are two versions
1) PSX. Standard Circuit Breaker. The -1, -2, -3 or -4 simply refers to how many PSX breakers are bundled together.
2) PSX-AR. The is the Autoreversing version of the single standard PSX. It still functions as a DCC circuit breaker at the same time.
Why PSX?
a) They have a trip current of 1.27Amps which is in range of the PowerCab Power supply.
b) They have a special mode that supports the PowerCab called "Weak Booster" when using Revision J boards. J7-3 and J7-4. Revision K board does not need it.
2) What Power Supply do you Have?
Possible means that some people have had inconsistent result. Majority work just fine. For those that have a problem, it is not possible to diagnose cause since there is no access to the layout to electrically evaluate operating conditions by someone who understands electronics/electricity.
The above assumes one is using the PowerCab's NCE manufactured FLAT CABLE. (Uses slightly larger wire gauge) Any substitution will result in less performance.
Last Updated
7/7/16
7/9/16