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Hacker/Jeti Mezon 90/95 safety warnings

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Old 09-05-2018, 07:28 AM
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bem
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Default Hacker/Jeti Mezon 90/95 safety warning

Hi,
I use Hacker Master Mezon 90 (with BEC) with Hacker Q80-14XS motor in my F3A plane since 3 seasons.
I read some days ago a safety warning that has its source from Hacker Motor, that is published at F3A Lorenz homepage in Germany.
I had one Mezon 90 stop to work in the air and it was toast and did not work after that incidence.
I have with the Mezon 90 I replaced it with several sudden stops when throttle was advanced during flight.
I think I need to change ESC for next season.

I have now read that Mezon 90 is not really suitable for our use in a 2M F3A plane.
Read below.
I also read a warning about Mezon Opto and third party receivers, I post that also below.

Just thought I would post it here to hopefully prevent any problem for people using any Mezon ESC described below in their F3A plane.
Translation is from German to English with Google translator, so myabe some not so correct translation but I think the most important info will be understood.

/Bo

Source (in German):
Hacker%20Regler%20Information.pdf
Information from Hacker Motor Service
Dear customers, there are still failures and fires of Master MEZON 90, Mezon 90 lite
and Mezon 95 opto
controllers when used in F3A models.
The reason is as follows: These controls are all too small for use in an F3A model!
Reason:
1. Mezon controllers are constructed differently than e.g. Master SPIN controller.
Only a few power transistors are used in the MEZON's (only 6 in the MEZON 90!),
which have to carry the entire current load.
With the SPIN 99, for example, many smaller MosFets are installed, which are distributed
over a larger area on the heat sink.
The heat dissipation is thus much better, the controller has better "taker qualities".
A MEZON 90 is therefore not comparable to a SPIN 99.
2. The phase currents are significantly higher under load than the indicated current in the controller.
A regulator should therefore always be designed 20% -30% stronger.
3. MEZON lite controllers also have a smaller, flatter, heat sink than normal MEZON controllers.
To make matters worse, that this smaller heat sink is also covered all around by the shrink tube of the regulator.
4. A reduction in the regulator opening in the transmitter brings no improvement, on the contrary, the controller gets even hotter in operation, since it has to tackle constantly and never fully through can. Deadly in the summer for the regulator.

Please inform your customers about these things when buying. Our recommendation for F3A use is either a Master MEZON 130 as a BEC controller, or at least a Master MEZON 115 Opto, better a MEZON 135 Opto in the optocoupler version. With these stronger controllers, the Lite version is conceivable, if not optimal.

With our F3A recommendations in the Hacker shop you will find no indication of the small Master MEZON controllers.

The argument for higher weight or additional costs certainly does not apply. When weight difference we speak of about 10 gramm, at the cost of a few euros. If a controller that is too small burns down, the damage is even more costly.
Thanks for your support. With your help we can certainly reduce new failures in the F3A scene.


Source (in German):
MEZON_Sicherheitshinweis.pdf
DANGER:
Safety advice for our customers!
Concerns the joint operation of third party receivers and JETI MEZON OPTO controllers.
Lately there have been very sporadic problems with the operation of receivers from other manufacturers when connected with a JETI Mezon OPTO speed controller.
Situation:If, contrary to the safety guidelines, not the drive battery is first switched off
by the controller, but first the receiver system, this combination may in rare
cases cause the motor to start unintentionally.

CAUTION!
Risk of injury!Since at the moment it is not yet clear which of these receiver / JETI-MEZON-OPTO controller combinations may cause this error, in the interest of your own safety we would like to ask our customers to disconnect the drive battery first and
then turn off the receiver power supply.

If this is not possible, we will prescribe a JETImodel Enlink 2RS Plus - DUO signal
repeater between third party receivers and JETI MEZON OPTO controllers.We have already informed the relevant manufacturers and will keep you up to date.In the interest of your safety, we would like to draw your attention in this connection once more to the safety and hazard warnings described in the instructions.

R/C systems should always be operated with due care and caution.If you have any questions, please contact our service team at any time.

Your team of
Hacker Motor GmbH









Last edited by bem; 09-05-2018 at 07:36 AM.
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Old 09-05-2018, 09:12 AM
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Thank you very much for posting this

It is very disappointing to hear but at least they acknowledged the design issues. I doubt there will be a trade in or replacement program offered.
I had heard of Mezon failures in helicopters but not planes.

I heard Scorpion now has Jeti EX bus Telemetry ESCís; maybe itís time to consider those?

Or go back to pre Mezon ESCs from Hacker (Spin Pro) and just add a Jeti MUI sensor to have capacity information.

ive got quite a few Mezon 90/95 ESCs that I should probably replace this winter
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Old 09-05-2018, 06:31 PM
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Hi,
I have Master Mezon 130 (with BEC) in two other F3A planes, since 2012, and thay have worked fine.
They are on the heavy side (15 gram heavier then Mezon 90).
Hacker Spin 99 Pro Opto is one option if one want a light (105 gram) ESC, but then one need a receiver battery
since it is an Opto ESC. The weight saving is eaten up compared to for example a Mezon 130 with BEC (weight 155 gram).

/Bo
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Old 09-06-2018, 04:49 PM
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I had 3 Mezon 90 Lite's burn up last year behind a C54/CRS contra. On Ralph Schweitzer's recommendation, I switched to the heavier Mezon 130 and it lived to finish the year behind the C54, but haven't flown it since. In June this year, had another Mezon 90 Lite fry behind a Pyro/Adverrun. Have not had other ESC failures except when I did the wrong thing, like put a an OS ESC behind a Q80.
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Old 09-07-2018, 08:54 AM
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Over on RCG, someone mentioned that the 90/95 Mezon is the same circuit board as the 115/130 ; they just used a smaller number of FETs.
They discovered this by opening up a unit and observing this.
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Old 09-08-2018, 03:10 AM
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Hi,
It is good that this info has been released by Hacker. To bad they did not figure this out long ago and added more number of FET's if that would help. My Mezon 90 blew up in 2016. Then I got a new Mezon 90, that I still fly with (but will not use it for next season). I had briefely a Mezon 130 in the plane where the Mezon 90 blew up but it was only while I waited for the new Mezon 90 to arrive.

It was long ago I tried something new in the motor and ESC field and maybe I will take the plunge for a Hacker Q80-14XS Sensitrol and Sensitrol ESC but that ESC is 151 gram and then I also need to add a 2 cell LiPo receiver battery (maybe 40 gram) and a "switch" like Powerbox Systems Digiswitch (15 gram), DPSI Micro SingleBat or DualBat 5.9V/7.2V F3A Edition magnetic switch (23-26 gram) or similar, all adding weight.
Another alternative is a Hacker MasterSpin 99 Pro Opto that has 48FET's, but it is kind of old ESC but I suppose still works good.
Thre is some new line of Jeti Mezon Pro ESCs to be released soon I belive and maybe I will wait and see their specifications.
But it seems they are only avaliable up to 80 Amp (100 gram) and that might be on the edge to low max current limit for use in many 2M F3A planes:
Jeti Model New Mezon Pro 50 ESCs with Full Device Explorer Integration, Wireless Programming & Telemetry!!! | EM Blog

/Bo

Last edited by bem; 09-08-2018 at 03:19 AM.
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Old 09-08-2018, 03:51 AM
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Hi,
Since I still have my Hacker Master Mezon 90 that burned up in 2016 I thought I might as well open it up and show what it is inside.
Enjoy
/Bo

Photo 1 and 2:
After taken the plastic label off the metal lid and then unscrew the 4 screws this is shown under the lid (no visable damage on this side of the curcuit board).






Photo 3:
On the other side of the curcuit board it is shown what has happened. Two FET's has burned and it is also shown black sot on the curcuit board. If I sniff with my nose on the black sot it still smell burnt. When this happened in 2016 it was in a flight flying a P17 manouvre, it was nr 3 Knife-Edge Combination with ľ roll, roll, ľ roll on about half throttle.



Photo 4:
Close details of the two burned FET's, more than half of the metal surface is burnt away.


Last edited by bem; 09-08-2018 at 04:48 AM.
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Old 09-10-2018, 03:22 AM
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I've been using the Mezon 95 OPTO Lite for some time now (in more than one F3A model) without any issues. This controller is rated for 95A continuous which is plenty for F3A. Peak currents would no doubt be higher than this. With any controller its always good to have good airflow over the heat sink. It should also be noted that the ESC has inbuilt over temperature protection. This feature is actually adjustable.

Regards,
Jason.
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Old 09-10-2018, 06:23 PM
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Originally Posted by Jeff Worsham View Post
I had 3 Mezon 90 Lite's burn up last year behind a C54/CRS contra. On Ralph Schweitzer's recommendation, I switched to the heavier Mezon 130 and it lived to finish the year behind the C54, but haven't flown it since. In June this year, had another Mezon 90 Lite fry behind a Pyro/Adverrun. Have not had other ESC failures except when I did the wrong thing, like put a an OS ESC behind a Q80.
I should have included that my ESC high endpoint and throttle ATV are set such that 72A is the max I've recorded from the Mezon logging. Normally it runs 69-71A flying AMA Masters. Last year during the first test flights, it was logging 90A peak so I quickly dialed back endpoints. (was more power than I needed too) Recent checks prior to my last failure in June still showed 70-72A peak. That should be plenty of margin for an ESC rated for 90A. Short of installing refrigerated air, I feel like I did what I could to keep the C54 and Mezon 90Lite cool.

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Old 09-10-2018, 07:11 PM
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Originally Posted by Jeff Worsham View Post




I should have included that my ESC high endpoint and throttle ATV are set such that 72A is the max I've recorded from the Mezon logging. Normally it runs 69-71A flying AMA Masters. Last year during the first test flights, it was logging 90A peak so I quickly dialed back endpoints. (was more power than I needed too) Recent checks prior to my last failure in June still showed 70-72A peak. That should be plenty of margin for an ESC rated for 90A. Short of installing refrigerated air, I feel like I did what I could to keep the C54 and Mezon 90Lite cool.
Yep, cooling looks reasonable to me. Surprised you're seeing such high currents from the CRS/C54. Are you using the recommended props?
The maximum I've seen on my CRS is 73A peak or maximum and I don't use any limiting at all. The average current (throughout a flight) would be much less than this figure.
It would be interesting to know what your ESC temps are. I've not measured mine but it's limited to 100C which I believe is the default.

Regards,
Jason.
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Old 09-11-2018, 01:03 AM
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Hi,
I think it is wise to follow Hacker own recommendations to not use Mezon 90/95 in an F3A plane.
I burned one Mexon 90 (with BEC) in 2016 as You can see in my photos above in post #7.
Although I have used a new Mezon 90 since that, in 2017 and 2018 seasons, that has so far not burnt up I probably use it on borrowed time so to speak.
Better safe then sorry, so at least I'm going to change to another ESC for next season.

After all Hacker say in their warning to not use it for our F3A flying.
Hacker write, as mentioned in earlier post:

"Information from Hacker Motor Service
Dear customers, there are still failures and fires of Master MEZON 90, Mezon 90 lite
and Mezon 95 opto
controllers when used in F3A models.
The reason is as follows: These controls are all too small for use in an F3A model!"

Hacker has obviously got reports and evidence from F3A flyers to make the descision and publish above info.

Obviously it does not matter that it is rated for 90/95 amp continous and You stay under that value during flight.
I have no depth knowledge in ESC's but I have been told that it is not at full power the risk is greatest to fry an ESC but it is at lower power settings like half throttle and such (my Mezon 90 burned at half throttle). If any knowledable person can explain how lower power usage creates greater risk for ESC failure it would be valuable.

/Bo

Last edited by bem; 09-11-2018 at 01:07 AM.
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Old 09-11-2018, 02:07 AM
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Originally Posted by bem View Post
Hi,
I think it is wise to follow Hacker own recommendations to not use Mezon 90/95 in an F3A plane.
I burned one Mexon 90 (with BEC) in 2016 as You can see in my photos above in post #7.
Although I have used a new Mezon 90 since that, in 2017 and 2018 seasons, that has so far not burnt up I probably use it on borrowed time so to speak.
Better safe then sorry, so at least I'm going to change to another ESC for next season.

After all Hacker say in their warning to not use it for our F3A flying.
Hacker write, as mentioned in earlier post:

"Information from Hacker Motor Service
Dear customers, there are still failures and fires of Master MEZON 90, Mezon 90 lite
and Mezon 95 opto
controllers when used in F3A models.
The reason is as follows: These controls are all too small for use in an F3A model!"

Hacker has obviously got reports and evidence from F3A flyers to make the descision and publish above info.

Obviously it does not matter that it is rated for 90/95 amp continous and You stay under that value during flight.
I have no depth knowledge in ESC's but I have been told that it is not at full power the risk is greatest to fry an ESC but it is at lower power settings like half throttle and such (my Mezon 90 burned at half throttle). If any knowledable person can explain how lower power usage creates greater risk for ESC failure it would be valuable.

/Bo
I looked for the Hacker information on not using these controllers in F3A but had no luck.

MOSFET's are most efficient when fully turned on. This is where their "on resistance" is specified. At lower settings (or switching frequencies) they will develop more heat (higher on resistance) and are less efficient.

Regards,
Jason.
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Old 09-11-2018, 02:51 AM
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Bo,

The FET's inside the ESC are rapidly switched ON & OFF as comanded by the throttle, at Full throttle the FET's are fully ON and in this sate have the lowest internal resistance, at part throttle the FET's are ON & OFF, the transition between ON & OFF is not instantaneous and the internal resistance of the FET is much higher during these transitions, so more heat is generated.
It is counter-intuitive but in general the ESC is more stressed at part throttle than full throttle.
Simple empirical tests (2012 post on RCG,) have been performed at full and partial throttle, with the current measured by a wattmeter at part throttle being half that of full throttle yet the ESC (shielded from prop cooling effects) temp rise after 1 min was around 15įC at full throttle and 45įC at part throttle !

Steve
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Old 09-11-2018, 09:05 AM
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Originally Posted by Jason Arnold View Post
Yep, cooling looks reasonable to me. Surprised you're seeing such high currents from the CRS/C54. Are you using the recommended props?
The maximum I've seen on my CRS is 73A peak or maximum and I don't use any limiting at all. The average current (throughout a flight) would be much less than this figure.
It would be interesting to know what your ESC temps are. I've not measured mine but it's limited to 100C which I believe is the default.

Regards,
Jason.
Props- 22x20R and 22x18F. Mezon temp limit remains at factory default settings.
I don't remember off hand what my peak current values were when running the C54/CRS, but they were well under 90A, and if I remember right, did not have to limit my high throttle end points to stay below 90A. The high throttle end point limits I was referring to above are with my current Adverun/Pyro setup, which replaced the C54/CRS. Yet still had Mezon 90Lite failure after about 225 flights on the Adverun.

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Old 09-11-2018, 04:17 PM
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Without getting too deep into semiconductor theory and other EE stuff, switching losses are a function of FET capacitance in addition to FET resistance.

Paralleling FETs opens another can of worms but ultimately you have to ensure that the FET(s) observe what is known as SOA (safe operating area)
You also have to manage power dissipation and thermal design

Clearly Jeti missed something in their analysis and itís a bit disappointing to be honest. Without seeing a schematic I canít tell exactly.

Disclaimer: Iím one of those EE types and Iíve designed brushless motor controllers in my past.
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Old 09-12-2018, 12:05 AM
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Hi,
So If I understand, it is the (over)heat that can kill an ESC at lower power usage? The current draw is obviously well below max continous allowed amp for the ESC if using half power for example.
So if one has a log (that Hacker/Jeti Mezon has, readable via JetiBox unless it is accessible via telemetry) ESC temp is the key thing to watch out for in this Mezon 90/95 situation to get less risk of burn the ESC?
At what throttle span is the ESC stressed the most so risk for failure greatest?

/Bo

Last edited by bem; 09-12-2018 at 05:55 AM.
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Old 09-24-2018, 05:03 AM
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I have a new plane fitted with an Mezon 90 lite controller, after reading this thread, I was reluctant to fly it. The motor I am using is OS with the reduction gear. However, others in Norway have 100's of flights with Mezon 90 lite/OS reduction gear combination, so I will give it a try. Reported max current 70-72A.

Here is the response I got from Jeti:
"The LITE version was developed for gliders with small fuselage. The most important parameter was size, so all parts were reduced to absolute minimum. For example, SPIN 99 PRO is designed for high loads, you can see differences at first glance. So if you want MEZON LITE for F3A (motor current 80A), I recommend MEZON 130 (or 160) and sufficient air cooling. All our official distributors know what the Mezon LITE is primarily intended for."

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Old 09-24-2018, 08:19 AM
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I use the Mezon 95 lite with Pletty in my Element and after 60 flights here in Greece with outside temps around 35-42 deg (summer) i don't have any problem..
I just fitted behind the air intake for best cooling results and after any flight i didn't measure over 55deg on the speed control.....
This combo works fine if you give your Mezon good cooling.... Also many top pilots fly with that combo...
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Old 09-25-2018, 01:51 AM
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The problem with using Mezon 90/95 (Non Light or Light, BEC version or OPTO version) is that it could work fine for long (or short) time and then BANG - it is fried FET's, like it was on mine. I had about 200-250 flights on my Mezon 90 (with BEC) when it got two fried FET's as shown in previous photos above. Then I mounted a new Mezon 90 again in the plane and it has worked fine during 2017 and 2018 seasons, probably about 500 flights. But You never know how long it will work like that. If You get a fried ESC in an unfavourable position over the flying field it may cause trouble to land in a normal way on runway. Landing out in rough terrain with our rather fragile F3A planes can be an expensive thing. And it is not for sure one is so lucky the ESC just fries, there is also the danger of a real fire in the plane when the ESC goes up in smoke. Then it can be really expensive flight.

/Bo
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Old 01-02-2019, 08:19 PM
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Default Mezon safety warning

In regards to the safety warning that states that shutting off an Rx before disconnecting the motor batteries could result in uncommanded motor operation.
That is exactly the case for my Mezon 115 opto/Futaba combination. Rx switch off and motor goes to full power. Seems like this can be overcome by adding a bec to power the Rx thus providing a continuous signal to the esc until the motor batteries are disconnected.
Thats a lot simpler than Jetiís solution to run a second receiver+battery with their electronic switching mechanism. Great for Jeti but not for owners of their defective escís.
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