Noise suppressing caps for brushed motors in the wet

[redboat219]

I know they only takes a few seconds to install but if you're running your DC brushed motors in the wet can you do away with those noise or spark suppressing capacitors?
Does the water "suppress" the noise?

[neitosub]

Not sure if water would suppress the electrical noise but it’s always a good idea to install capacitors on brushed motors. They are pretty straightforward to install, you need a soldering iron that’s at least 45W.

[Sam Victory]

Electromagnetic waves are everywhere, and there are two main ways of propagation: the first is conduction, and the second is radiation. Obviously in RC submarines electromagnetic wave interference is in the form of conduction, no matter where the motor is placed, the wire to which the motor is connected is the medium for electromagnetic wave conduction. We know that there is always a coupling phenomenon in the actual circuit, the so-called coupling is commonly understood as "contact", the existence of resistance and capacitance in the circuit will be a coupling medium, the motor generated or output voltage signal (which can actually be understood as a kind of energy, the output of the circuit) transferred to another part of the circuit. So the best way is to install a filter module to the receiver (ordinary ppm receivers are relatively small and can not put a filter capacitor), can be an anti-interference filter capacitor. I think the less troublesome way is to install a BEC module to the receiver (this is an operation that cannot be omitted), the better BEC module comes with a filter circuit, effective anti-interference (you can refer to Mr. Merriman's Hunley submarine, the receiver installed BEC has good filtering effect, and also comes with a filter magnetic ring). Many advanced BEC modules come with a large capacitor, that is the anti-interference filter capacitor. There are two main types of filtering: software filtering and hardware filtering. Common software filtering algorithms such as DSP filtering algorithm, Kalman filtering...etc. Hardware filtering mainly relies on filtering circuits.
There are many other examples of filtering (denoising), for example, Sony has a product: wh-1000XM4 noise cancelling headphones. The electronic module inside the headphones is the use of high-tech filtering circuitry and denoising algorithms, except that the removal is the sound signal. As to whether the sound signal is first converted into a voltage/current signal, this is just my guess, according to common sense.


V



I have purchased several PPM receivers of the "Henge" brand, which have the following characteristics：

1. rp82l 8-channel double conversion integrated receiver is a receiver with free frequency conversion.

2. automatic scanning and locking of the transmitter frequency can be achieved with "one button control".

3. excellent reception performance, reception distance up to 1 mile.

4. Dual tuned ceramic IF filters ensure accurate sensitivity and resist interference from adjacent channels.

5. able to automatically identify and perfectly match the following transmitters: futaba, jr, WFLY.

6. "DSP" filtering technology can intelligently filter noise to improve the receiver's anti-interference performance, more suitable for use in complex environments.

7. loss of control protection can lose signal reception in the case of the predetermined position of the servo.

[redboat219]

Electromagnetic waves are everywhere, and there are two main ways of propagation: the first is conduction, and the second is radiation. Obviously in RC submarines electromagnetic wave interference is in the form of conduction, no matter where the motor is placed, the wire to which the motor is connected is the medium for electromagnetic wave conduction. We know that there is always a coupling phenomenon in the actual circuit, the so-called coupling is commonly understood as "contact", the existence of resistance and capacitance in the circuit will be a coupling medium, the motor generated or output voltage signal (which can actually be understood as a kind of energy, the output of the circuit) transferred to another part of the circuit. So the best way is to install a filter module to the receiver (ordinary ppm receivers are relatively small and can not put a filter capacitor), can be an anti-interference filter capacitor. I think the less troublesome way is to install a BEC module to the receiver (this is an operation that cannot be omitted), the better BEC module comes with a filter circuit, effective anti-interference (you can refer to Mr. Merriman's Hunley submarine, the receiver installed BEC has good filtering effect, and also comes with a filter magnetic ring). Many advanced BEC modules come with a large capacitor, that is the anti-interference filter capacitor. There are two main types of filtering: software filtering and hardware filtering. Common software filtering algorithms such as DSP filtering algorithm, Kalman filtering...etc. Hardware filtering mainly relies on filtering circuits.
There are many other examples of filtering (denoising), for example, Sony has a product: wh-1000XM4 noise cancelling headphones. The electronic module inside the headphones is the use of high-tech filtering circuitry and denoising algorithms, except that the removal is the sound signal. As to whether the sound signal is first converted into a voltage/current signal, this is just my guess, according to common sense.


V



I have purchased several PPM receivers of the "Henge" brand, which have the following characteristics：

1. rp82l 8-channel double conversion integrated receiver is a receiver with free frequency conversion.

2. automatic scanning and locking of the transmitter frequency can be achieved with "one button control".

3. excellent reception performance, reception distance up to 1 mile.

4. Dual tuned ceramic IF filters ensure accurate sensitivity and resist interference from adjacent channels.

5. able to automatically identify and perfectly match the following transmitters: futaba, jr, WFLY.

6. "DSP" filtering technology can intelligently filter noise to improve the receiver's anti-interference performance, more suitable for use in complex environments.

7. loss of control protection can lose signal reception in the case of the predetermined position of the servo.

Or I could just take Nate's advice and spend a few seconds soldering on some caps.

[Sam Victory]

Or I could just take Nate's advice and spend a few seconds soldering on some caps.

Yes, it is necessary to solder capacitors to the motor. But an additional BEC is also needed, not just to eliminate electromagnetic interference from the motor. Mr. Merriman's words in this link can better state the facts：Revell Gato 1/72 - Newbie no more Part duex - The Sub-drivers Forum (rc-sub.com)

V

[gantu]

[Bob Gato]

Note: Many modern brushed motors already have capacitors -you sometimes can see them thru the vent holes or see the end of their wire sticking up thru where the backplate is crimped/pressed into the can.

[redboat219]

Guess you really need to install caps. Even if water can block the RF noise there's still the line noise.

Electromagnetic interference(EMI) are classified into the following 2 types.

dBμV	Noise that travels through power cables and connection cables.	0.15 - 30MHz
dBμV/m	Noise that is radiated from the source to the air and causes interference in TV and a radio.	30 - 1000MHz

[redboat219]

Source: https://www.mabuchi-motor.com/produc...nce/noise.html

[neitosub]

Yes, it is necessary to solder capacitors to the motor. But an additional BEC is also needed, not just to eliminate electromagnetic interference from the motor. Mr. Merriman's words in this link can better state the facts：Revell Gato 1/72 - Newbie no more Part duex - The Sub-drivers Forum (rc-sub.com)

V

I would test the RC setup without a dedicated BEC first. You have to keep in mind that many of the existing 75mhz receivers are simply surface versions of popular 72mhz receivers for model airplanes, and those have been operating fine without a dedicated BEC for years. I don’t mean using a separate 4.8V battery pack to power the Rx, but rather powering the Rx with the 3-pin plug from the ESC. Solder capacitors on the motors and run a test with all the servos hooked up.

[He Who Shall Not Be Named]

To Gato's astute observation that some brushed motors come equipped with internal spark-suppression capacitors, I offer these examples. As he noted, the small wires projecting out from within the motors back-plate, wrapping around the external poles, is an indication of installed cap's. Such as these examples.




Looking at the inside of the motors back-plate you see one leg of each capacitor press-fit to a brush holder, the other leg projecting aft, outside, and wrapping externally around the lug that is part of the brush-holder. That's how current is sent to the switch-commutator. The parallel situated capacitor shunts spikes (an artifact of mechanical switching) to ground, the motor case itself.





During our early association with the Caswell Company Mike worked to get the Chinese manufacturer of the motors we used to build batches with installed capacitors, this move saved us from the labor of doing it ourselves and sped SubDriver production to a significant degree. There is profit in quantity buys -- just another good business lesson Mike passed on to us.

Keep it simple: Just two capacitors are needed to reduce the magnitude of the voltage spikes created by the sparking commutator-brush, no matter the motor size or number of poles.






David

[He Who Shall Not Be Named]

I would test the RC setup without a dedicated BEC first. You have to keep in mind that many of the existing 75mhz receivers are simply surface versions of popular 72mhz receivers for model airplanes, and those have been operating fine without a dedicated BEC for years. I don’t mean using a separate 4.8V battery pack to power the Rx, but rather powering the Rx with the 3-pin plug from the ESC. Solder capacitors on the motors and run a test with all the servos hooked up.

Trouble is: most ESC BEC's don't have the ass (1.5A max) to drive the device heavy environment of a typical r/c submarine.

Your typical plane needs the BEC to power only three or four mini-servos that are lightly loaded.

A submarine has at least that many servos, that are heavily loaded as well as angle-keeper, LPB switch, fail-safe, magnetic switch, receiver, depth-keeper, and god knows what other whiz-bang-deep-sea-wonder device that have been installed to suck the life out of that poor little ESC BEC.

You Monsters! How dare you (hi there, Greta!).

No. As a matter of course, for any but the very small WTC's (2" and smaller diameter, because you can't fit all that crap into a tiny cylinder), you need a dedicated BEC good for at least a continuous 3Ampere output.

Hotel services are everything -- you fry the BEC, you stand a good chance of losing the boat! At the very best you have to paddle out to retrieve it.

Better too much BEC than too little!

David

[neitosub]

Yes for a larger boat with many features a BEC would be needed as the current draw is much larger. From Romel’s Facebook post he was referring to running tests on a 1/35 X-Craft, which is a small sub. For compact size subs, I think you can get away with not running a dedicated BEC, this all depends on the specific model of the receiver of course!

[He Who Shall Not Be Named]

Yes for a larger boat with many features a BEC would be needed as the current draw is much larger. From Romel’s Facebook post he was referring to running tests on a 1/35 X-Craft, which is a small sub. For compact size subs, I think you can get away with not running a dedicated BEC, this all depends on the specific model of the receiver of course!

Totally agree. For the most part. However, even small WTC's can quickly become burndened with more nodes of hotel demand than you would first think.

https://youtu.be/Lu6x3vI2Yek

https://youtu.be/4Vk3n3qXOso

David

[Bob Gato]

Thanks David for the visual assist on factory internal noise suppression -here's one that is less obvious from post #6 -the pole connection is internal and the only indication (short of disassembly) is this can connection-There are many motors out there that also have owner unknowingly installed external caps...Probably not not a real issue other than being unnecessary work.