Electronics - Stator Gator - What is it?

[carey shurley]

I've gotten a few questions asking about the Stator Gator, what is it and how to connect it so I put this together to better explain it.

So what exactly is a Stator Gator and why do I need this thing? Well first lets start off by explaining a little bit about why you might want one of these

Governors

Because the throttle curve characteristics of a gas helicopter are very different than that of glow models, the setup is greatly simplified by using a governor. However mounting the governor sensors on gas models is usually more difficult because the motor format and cooling system is very different from a typical glow model

Here's a typical governor and the sensor it uses to sense RPM. The sensor is known as a "hall effect" sensor which uses the effects of a magnetic field to vary the output voltage it produces.


Typical Governor with Hall Sensor

the key to the system is installing a small magnet and mounting the hall effect sensor close enough for it to measure the field change. Here you can see a typical magnet and where its mounted in a fan. This is always accurate because the fan is locked to the crankshaft but its more difficult to get the sensor mounted close to this magnet


Typical sensor magnet and fan

some of the newer models allow the magnet to be mounted in the clutch bell. Its easier to get a sensor mounted for this but if for some reason the clutch is slipping, the governor will start to increase the throttle to compensate for a lower RPM which of course will probably make the slippage problem worse and it will continue to add throttle, etc.

In both of these methods, its not uncommon for the sensor itself to eventually get loose from the vibrations which results in the governor failing at least until the sensor is repaired or replaced

Some of the newer governors are using crank position sensors which eliminates the need for magnets because it uses the metal mass on the crankshaft as a trigger. Again the issue is how to mount the sensor, some of the newer motors come with a special backplate that this sensor will slide into


Clutch mounted sensor magnet

The Stator Gator

So a few years ago, a guy named Tom Fiddler found a way to solve this problem for our gas motors. He created a device that reads the pulse from the ignition coils and converts it into a pulse that can be fed into a governor. From the governor, it looks just like the signal coming from the hall effect sensors but it doesn't require any magnets or sensor to be mounted.

Here's a complete Stator Gator


The Stator Gator

and here you can see that there is a sensor wire which connects the SG to the RPM sensor port on a governor. We'll cover the other connection shortly


SG connected to a governor

This is the main part of the SG. Its a small plastic case that contains some circuitry, its sealed in epoxy and is not serviceable. This piece gets mounted somewhere on your model, I typically use velcro or two sided tape. It produces no harmful radio emissions so its location is not critical. In some of the early testing they literally wrapped 72mhz rx antennas around the SG itself and its wires and it made no difference in control


The central part of the sensor

So in order for this to work, the SG sensor has to be connected to the ignition system on the motor so it can count the RPMs by the number of times it fires the spark plug

Types of Stator Gators

Because the Zenoah/CY motors use 3 different ignition systems, there are 3 different Stator Gator systems and each one connects to the ignition system in a slightly different way. Here are the 3 types:

The Stator Gator GGS23 which is for use on the RC format motor


SG for Zenoah/CY RC motor

The Stator Gator GG23 which is for use on the PUH format motor


SG for Zenoah PUH motor

and the Stator Gator 20-26 EI Series which is for use on the Zenoah EI system motors


SG for Zenoah EI

Next Up:

How do the different Stator Gators connect

[carey shurley]

How Do You Connect a Stator Gator?

As stated, there are 3 different ignition systems on the Zenoah motors we use and so 3 different methods of connecting the stator gator is required

PUH Format

On the PUH format motor, the ignition system is made up of two coils, a red primary or trigger coil that mounts above the magneto/flywheel and a high voltage coil that connects to the spark plug.

This version of the Stator Gator connects to the black wire or ground of the primary ignition coil as shown here. There are two connections on the SG, one of them plugs into the black wire and the other needs to be grounded to the motor or the ignition coil itself. These remain connected unless its necessary to remove the motor or the SG


SG connected to a PUH trigger coil

EI Format

On the motors that use the Zenoah electronic ignition, there is a single ignition box that connects to a sensor on the crankshaft, a power source and to the spark plug itself

This version of the Stator Gator connects in between the crank position sensor and the ignition unit. Because Zenoah uses somewhat unique connectors, this is simplified because the connectors on the SG unit will only connect to the correct components. These remain connected unless its necessary to remove the motor or the SG


SG connected to a Zenoah EI system

RC Format

On the RC format motor, the SG connection is made by replacing the push botton "kill switch" found in the cooling shroud of the motor with an SG connector

here you can see the original kill switch and the end of the RC format SG. The switch can be easily removed from the motor using a screwdriver


RC motor kill switch

The two connectors that attach the kill switch are removed and then connected to the SG pickup as shown.


Kill Switch Removed

One note here, there is a red and black wire. The SG pickup has a denoted red terminal. Typically you'd think that you'd want to connect the red wire to the red marked terminal but more often than not you have to do just the opposite to make this work. More on this later


SG connected to an RC ignition coil

when you push the SG connector back into the motor it looks like this


SG installed on RC motor

Optional EI

there is an optional connection for the EI version of the SG. If your motor is using the RCExL ignition system, the new ones have an RPM sensor wire thats made to plug into the RCExL tachometer. Its just a std Futaba J connector. The pulse that comes out of this matches the engine RPM so it can be used to trigger SG. The voltage that is on this circuit is far too high to plug directly into your governor so don't be tempted to do that. It will work...........for a while until it damages your governor

So what you have to do here is to cut off the two Zenoah EI connectors and just install a single male Futaba J connector in its place. Make sure you get the connector polarities correct. Now you can just plug the SG directly into the RPM sensor wire on the RCExL ignition. The SG will protect your governor from the high voltages on the ignition system and this will work fine.


RCExL ignition RPM sensor

Mounting the sensor

mounting the sensor itself is not critical, it can attached with tape, velcro, tie wraps or rubber bands, its location is limited only by the lengths of the wires

One thing to note is that on the RC version, its more complex to remove the pickup from the motor whereas the PUH and EI versions can be unplugged. On some models, you can't easily access the pickup in the side of the RC motor without removing parts from the model so if you need to remove the motor for some reason be aware that you may need to remove the SG as well.

Here's a typical mounting of the SG unit


Typical mounting for SG

Problem Solving

This is pretty easy because practically speaking these things just don't fail. The circuits inside just work. They don't cause any radio interference or any other system issues

There are only a couple of things to look at if your governor appears to not be receiving the signal from the SG and you think there is a problem.

Connections

Check the connections, make sure they are connected and there are no broken wires. For most supported governors this is about the only thing that can go wrong

If you are connecting the SG to an RC format motor, there are sometimes polarity issues with the ignition coil wires. Depending on the exact coil you may need to connect the black wire from the coil to the red marked pole on the SG pickup. There is no simple way to determine this other than testing the unit. If your governor doesn't pick up a signal from the SG OR when you check the Max RPM setting on Futaba governors and the number is zero, try switching the red and black connectors. This is ONLY applicable to the RC version.

Futaba 701/750

you have a Futaba GY701 or GY750 and are installing on a PUH/RC motor, you MUST add a voltage jumper. The GY701 and 750 systems operate at a lower voltage than the GV1 and other governor systems. As a result SG requires Rx voltage to work properly.

If you do NOT use a voltage jumper, Max Sensitivity reading on the governor will be less than 99% and your governor will not operate properly. Remember this can only affect Futaba 701/750 governors and only the PUH/RC versions

Contact Stator Gator, they've made these up for simple installation. They are connected in as shown:


SG Voltage jumper for GY701/750


Stator Gator - Governor Compatibility Chart


Finally, I get a lot of questions regarding the Stator Gator sensor and what governors it will work with

here's the official list from Stator Gator by product

GG23/GGS23 - Zenoah/CY PUH and RC Sensor

• Futaba GV-1
• Futaba GY701 (may require voltage jumper)
• Futaba GY750 (may require voltage jumper)
• GS/CSM
• Mikado VBar

20-26EI Series (Zenoah or RCExL Electronic Ignitions)

• Futaba GV-1
• Futaba GY701
• Futaba GY750
• GS/CSM
• Mikado VBar
• Multi-Gov
• Rev-Max
• CYE-ATG

If your governor isn't on the list, it probably won't work. The list is specific to sensor type, the governors that are uniquely listed for the EI version will NOT work with the RC/PUH format sensor or motor

The Bottom Line


A couple of years ago, production and sales of the Stator Gator was taken over by Adam Mancini and Chris Streitberger. They continue to evolve the stator gator and expand the number of governors/limiters that it will work with

The Stator Gator is the simplest, most trouble free method of connecting a governor to your Zenoah gasoline motor, and I highly recommend using it. There are other ways to connect hall effect sensors to your model but over time they will usually become problematic

for more information on the Stator Gator, visit http://www.thestatorgator.com/

[ocr231]

This looks awesome.Fantastic job as always.

[Eleven_Bravo]

Will the stator gator work with a CGY/750 and will these two work with a DX-7??

[carey shurley]

yes SG works with the GY750 although it probably will require the voltage jumper shown

to use the 750 with a spektrum radio you need the Futaba PWM/SBus adapter because the 750 requires having SBus to connect to the receiver. This adapter is available from Futaba/Tower now

[Mr.HillBilly]

I picked up my SG at IRCHA last year, and I am using it with the CGY 750 on a 231 PUH with no probs. at all. Since I run Airtronics I have the SBus adapter also, I have over 140 flights on my Radikal and everything has worked great with no issues.

Give it a try without the voltage jumper and see if it works.

[AlvaSpeed]

So how do you turn off the Rc type engine if you remove the kill switch?
Low throttle position?

[carey shurley]

I always setup the throttle butterfly so that it closes completely. Unless you've got an air leak the motor will stop at that position

or, if your carb has a choke on it, you can just close that or if not the air cleaner will have a choke on it and you can close that. motor stops instantly

[cbergen]

Just to add, the SG sensor also works well with the DJI series of Autopilots.

[PeterW]

Will the Stator Gator work with a VBar 5.2?

I tried to get it to work last summer (2010) and it did not work

Do I understand you correctly that if I buy a new sensor (Stator Gator) and it should work now?

[carey shurley]

the EI version will, but out of the box its configured for the G20 EI. If you have an RCExL ignition, you can replace the sensor connector with a std Futaba connector and plug it into the Tach connector on the EI unit

dunno if the RC/PUH versions will work

[blackbeard]

This was helpfull THANKz ]

[Seasick78]

Here is another example of the required voltage jumper that has been discussed as needed for the CG701/CGY750.

A standard extension can be used. Just clip the yellow/white wire from the female connector. Then seperate (peel away) that wire from the other two. Using a spare female connector, pin the seperated wire and install the newly pinned wire into extra female connector. This wire will plug into the RSen port on the CGY750. Depending on your setup, the other female connector will plug into either the receiver or any open power source that you have (the voltage regulator, or whatever else you want to use). The male (socket) connector is what you plug the stator gator into.

This works well if you have the special pliers needed for crimping the pin for the connector. This way also avoids the need for any soldering and/or splices. The one I have depicted in the images below took about 60 seconds to make and works like a champ, providing a 99% indication on the CGY750 in the governor sensor setup menu when installed and tested.











--Josh

[cbergen]

Why did you cut the yellow wire? You can simply remove the pin from the plastic connector and insert it into another one.

[Seasick78]

Yep... Can do it either way. Had the spare pin and went that route. Do it with the original pin and no special pliers are needed. Will only take about 30 seconds instead of 60 seconds.

In either case, its WAY better than paying someone else $20 to make one and ship it to you several days later.

[PeterW]

Someone who can answer how much volts I can give the StatorGator?

7,4v ??

[carey shurley]

Hey Peter

I asked Adam who helps make the thing, the IC is rated at 25V so anything less than that is okay. More than that use an inline resistor

[jockstrap]

Any idea if the Stator gator (or a GV1 sensor) will work with the new Skookum SK540 fbl gyro ?

[carey shurley]

the mfgr has not tested it and does not know if it will work

[desertstalker]

Originally Posted by jockstrap

Any idea if the Stator gator (or a GV1 sensor) will work with the new Skookum SK540 fbl gyro ?

The SK720 and 540 use the same type of sensors as a VBar, so if it works for that there is no reason why it shouldn't work for a SK.