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FAQs

Can I purchase any or your controllers or modules off the shelf?

Do you make speed controllers with reverse?

What is a mosfet?

What is PWM?

Can I have a controller for a special purpose, not just RC?

Why does the LED on my speed controller continually flash?

Why, after programming my speed control, does the LED do short flashes?

Why does your speed control only have 3 power wires?

What sort of guarantees do I get when I purchase one of you devices?

When a new program version comes out, can I have the program in my control upgraded?

Other brands specify current ratings higher than yours, aren't their controllers more powerful?

 

 

 

Can I purchase any controller or module off the shelf?

        Yes, only the ones I have in stock at the time. This is not a commercial company. I only build modules/controllers as demand and time allows. I have a full time job, this is a hobby. To find out if a device is available for immediate purchase, or what the delivery time will be, please inquire.

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Do you make speed controllers with reverse?

        I have looked at this a number of times. I have a couple of designs, but there are a few reasons why I  haven't pursued it.

  • Firstly the component count is much higher, which would add about 70% to the materials cost.

  • With the extra components, the controller would be much bigger.

  • Having reverse in a controller requires the use of a "H" bridge arrangement. "H" bridges require mosfets connecting the motor to the positive side of the battery as well as the negative side. At a bare minimum this doubles the on resistance of the controller, which reduces the peak performance, increases the heat loss and reduces the possible power output to about 70% of a controller with the same number of negative connected drive mosfets. So for increased power in a small package at the best price, forward only with brake is best.

  • International racing rules do not allow reversing during competition.

If you would like to know how much, send us some specs and I'll send you a quote. Inquire

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What is a mosfet?

        Mosfet is an acronym for Metal Oxide Semiconductor Field Effect Transistor. It is basically a solid state switch that is controlled by a voltage input. They can be switch on and off very quickly and when on the resistance to current flow is extremely low. The mosfets I use are ~3.2mW (0.0032 ohms) when turned on. By connecting a number in parallel, even lower resistances are achieved. There are 2 types, N channel and P channel. N channels are most common, are cheaper, come in lower resistance values and generally connect the motor or output to the negative terminal of the battery, but with special circuitry can be used to connect to the positive terminal. P channels are normally used to connect to the positive terminal.

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What is PWM?

        PWM stands for Pulse Width Modulation. Most modern power control is done using mosfets, which are high speed switches. PWM is a method for varying the output power by switching the output to full power for a very short period and then off. This is performed over and over at high frequency, usually from about 1 kHz (1000 times per second) up to around 100 kHz (100,000 time per second). The power is varied by changing the ratio of on time to off time. Because the switching makes an audible noise like the cracking noise you here if you turn off a hose quickly, frequencies in the range of 8 kHz to about 18 kHz are normally avoided to prevent discomfort from the sound.

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 Can I have a controller for a special purpose, not just RC?

        Yes, I will build or modify a controller for any purpose. Check out the Super Servo Driver Card  & PM Bench Tester for example Ask for a quote.

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Why does the LED on my speed controller continually flash?

        All my controllers have a no signal telltale. The LED flashes continually at about 1/2 second intervals to indicate it is not receiving a signal. If you have this problem please check the following.

  • Check that the radio is turned on.

  • Is the controller plugged into the receiver. Check the connections.

  • Does a servo work in the same receiver, if not then you have a radio problem. Check crystals are OK and the same frequency, and check you have battery power in the transmitter.

  • If the servo works and the LED still flashes, check the signal wire and plug for damage and try another receiver channel, i.e. try plugging into the steering channel.

 

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Why, after programming my speed control, does the LED do short flashes?

        If after programming a controller the LED flashes for short flashes followed by long spaces, the controller is indicating it can't use the values you entered. Specifically, you entered a Neutral value that was higher than the Full Throttle value. Please check the programming sequence and program again. If you have lost your spec sheet you can download a new one from here.

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Why does your speed control only have 3 power wires?

        Most forward/brake only controllers have the Battery + and the Motor + wires soldered together in the circuit board. This takes up board space and increases overall circuit resistance due to the board connection, solder joints and extra length of wire required. In the interest of weight and maximum power, it is better to connect the positive wire directly from the battery to the motor. If you need to have a motor that unplugs, connect the battery positive directly to the motor plug.

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What sort of guarantees do I get when I purchase one of you devices?

        I guarantee that my devices will perform up to the specifications supplied with the device. If not, return it for repair, or in good condition for a refund. In addition all components and workmanship guaranteed for the life of the controller. Also I will repair any of my devices at the cost of components plus time, for any device which has suffered from abuse. Note that all freight costs will be the responsibility of the purchaser.

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When a new program version comes out, can I have the program in my control upgraded?

        All devices from now on are flash memory re-programmable. If the actual type of micro controller hasn't changed, then I can reprogram your device. The cost is AUD $15 plus freight/postage. Please check first.

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Other brands specify current ratings higher than yours, aren't their controllers more powerful?

        Most brands of speed controllers tend to overate the current capabilities of their devices, or give a rating based on a short time interval, particularly in the cheaper ranges, but also in the expensive brands too. This makes for good sales, but not good reputation. All my devices are tested and guaranteed to handle the currents and voltages specified, with the standard rating now being for 10 second duration (150 Amps for Power Master). I have seen many controllers shut down in the middle of a race or burn out when they were being used well within their specs. So be careful. I would de-rate an expensive controller by a minimum of 20% and a cheap one by up to 70% if I were going to buy one.

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This website last updated Monday, 06 November 2006