PDA

View Full Version : Servo Question



arch2b
03-21-2005, 07:24 PM
i need some answers regarding the use of micro servo's. these are not used much nor discussed much on mini-zracer so i thought i would check with the guys here who are used to seperate electronic components.

here is the situation...
i am building a 1:32 CRT using the mr-02 electronics (pcb) coupled with a HS-56 micro servo. the mr-02 pcb will handle up to 10v, the servo is rated for 4.8-6v.

i would like to use the atomicmods 8.4v li ion 2 cell pack. it's just the right size and all. the problem is i know the stock mr-02 pcb can handle it but i am not sure about the servo used in conjunction with the mr-02 pcb :confused:

my CRT gallery (http://www2.mini-zracer.com/gallery/album585)

atomicmods mr-02 page (http://www.atomicmods.com/Mini-Z_MR02.htm)

here are the specs for the HS-56 (http://www.hitecrcd.com/Servos/hs56.htm)

arch2b
03-22-2005, 03:20 AM
wow, no bites... i would have thought that someone would know based on the, way over my head, motor and battery pack discussions elsewhere....

RURC
03-22-2005, 04:35 AM
here is the situation...
i am building a 1:32 CRT using the mr-02 electronics (pcb) coupled with a HS-56 micro servo. the mr-02 pcb will handle up to 10v, the servo is rated for 4.8-6v.

i would like to use the atomicmods 8.4v li ion 2 cell pack. it's just the right size and all. the problem is i know the stock mr-02 pcb can handle it but i am not sure about the servo used in conjunction with the mr-02 pcb
First as I see it you have a discrepency. Li ion cells are 3.6 v per cell. That puts a 2 cell at 7.4 not 8.4. I think you must have hit the wrong key. Now on the servo. That voltage will most likely burn it up. If not it WILL greatly decrease its life span. One thing you need to know is the output of the mr-02 pcb to the servo. Most controllers dedicate spicific voltage to the servo. However I have no idea as to weather yours dose that. I know that on the CC Mamba controller when you tell it what battery you have is automatically adjusts to only allow 6.0 volts to the rec and servo. If I remember correctly the mr-o2 uses a racknpinion steering servo. If I am correct this was most likely special made for that car. Thuss, designed and made to work on 10 volts to cut down on the materal costs for the pcb. If you have the output voltage in the correct range there might be no problem. You still do not know the control modulation going to the servo. Most likely the same but.... the other fix would be in the wire harness. I am sure that you have a very good electronics supply store in your area. Go there and see if someone could make a voltage limiter that you just plug in line with the servo. As long as the control voltages are not out of line. Sorry not to be much help. But I did give you a lot of home work.. :D

Call HiTec and ask them if it will handle it I bet it wont.

BitHed
03-22-2005, 05:56 AM
...so to hijack Arch's thread, kind of, if i want to get a NEW servo for the halfeight it needs to be able to handle 9.6 volts? And the ESC needs to be able to handle that too ? i had a quick look at FUTABA and so far everything is limited to 7.2 volts...Am i looking for the right thing ? I knew ZERO tech knowledgw was going to be my downfall...Now i have to ask for advice again :p

tunnelhead
03-22-2005, 06:27 AM
Why couldnt you use one of Novaks 6 volt voltage regulators? Wouldnt that drop the voltage from 9.6volts to 6. They use them on the Li Po oacks when you use them for a reciever pack for the nitro cars. Then you could use any ESC and servo. Am I wrong? Woundlt be the fisrt time I am wrong and forsure wont be the last. Enlighten me oh mighty ones.

BitHed
03-22-2005, 06:29 AM
...That sounds kinda cool...but then is the car running at 6V or 9.6V ?

tunnelhead
03-22-2005, 06:31 AM
Problem solved? Novak products. Nitro Servo Regulator #5460 at $29.00

BitHed
03-22-2005, 06:34 AM
...makes sense and its quite a happy price...what do the techs have to say? Tunnelhead do you have a link for that?

tunnelhead
03-22-2005, 06:35 AM
hmm not sure about that bithead. Might have to call them on that, Where are all them techno savy peole when you need them

tunnelhead
03-22-2005, 06:38 AM
try this bithead

www.teamnovak.com/Buy/ind_buypgs/5460.html

are you in Japan bithead?

BitHed
03-22-2005, 06:40 AM
...yup...about an hour north-west of Tokyo...Its cold and overcast...and its 445pm...

Captain Bit
03-22-2005, 06:49 AM
Hi Mate, The electric motor works on the maximum voltage you can stoke into it.
The receiver and servos should only have 4.8 or at the maximum 6 volts up them or they may take an early lunch.
If they are fed through a regulator from the main battery then they will be happy little campers. Good luck.

BitHed
03-22-2005, 06:51 AM
...well well well...Look what the cat dragged in...Captain Bit are you sure you can keep us with us car fellas? We would'nt want you to get the wind taken out of your sails...Glad to have you here all the way from the Long White Cloud ;)

tunnelhead
03-22-2005, 08:40 AM
Bithead why are you playing with rc cars when you should be out playing with Skylines and them other awsome cars from japan

tunnelhead
03-22-2005, 08:46 AM
well my choice of car would be the 1969 Syline GTR PGC10 with the S20 engine. 2L 6 cylinder dual over head cam, 4 valves per cylinder. . Sell my soul for that car.

arch2b
03-22-2005, 10:35 AM
First as I see it you have a discrepency. Li ion cells are 3.6 v per cell. That puts a 2 cell at 7.4 not 8.4. I think you must have hit the wrong key. Now on the servo. That voltage will most likely burn it up. If not it WILL greatly decrease its life span. One thing you need to know is the output of the mr-02 pcb to the servo. Most controllers dedicate spicific voltage to the servo. However I have no idea as to weather yours dose that. I know that on the CC Mamba controller when you tell it what battery you have is automatically adjusts to only allow 6.0 volts to the rec and servo. If I remember correctly the mr-o2 uses a racknpinion steering servo. If I am correct this was most likely special made for that car. Thuss, designed and made to work on 10 volts to cut down on the materal costs for the pcb. If you have the output voltage in the correct range there might be no problem. You still do not know the control modulation going to the servo. Most likely the same but.... the other fix would be in the wire harness. I am sure that you have a very good electronics supply store in your area. Go there and see if someone could make a voltage limiter that you just plug in line with the servo. As long as the control voltages are not out of line. Sorry not to be much help. But I did give you a lot of home work.. :D

Call HiTec and ask them if it will handle it I bet it wont.
thank you for your reply. like bithed, i know little to nothing about sperated electronic components.
it's sounds logical that the mr-02 pcb regulates the voltage to the servo as many have run 6 cel mini-z's and this same li battery pack is made for the mr-02. i just never realized the pcb could or would do that. i like to think of my CRT project as an introdcution to larger scale rc electronics so i'mgreatful for the learning experience. unfortunatley i had to take the cheaper route and start with the mr-02 pcb instead of micro esc and receiver. next time i'll have to pony up for the right stuff ;)

no worries about jacking the thread bh :cool: the issues are virtually the same just larger scale. it also helps prepare me for when i get my h8 :p

BitHed
03-22-2005, 02:58 PM
...I though so too Arch...Thats why i took the liberty :) You see my dad posted in this too? Thats pretty cool...

...I liked the look of the NOVAK NITRO SERVO REGULATOR...might not be reasonable for what you need but i learnt some good stuff...

chrille
03-22-2005, 03:10 PM
BitHead, this is so simple that it becomes fun...the only thing that you`ll have to look on is if the speedcontrol can handle 9.6V! :D Then the speedcontrol will fix it so that the servos and reciever will get only 5V, simple huh!? So you do not need to wory about the servo limited to 6 or 7.2V!

ruf4play
03-22-2005, 03:12 PM
If you use regular electronics, the esc will have a battery eliminator circuit that regulates the voltage down to the appropriate levels for the rx and the servo. The last time I looked at the MR02 pcb, I didn't notice any voltage regulation circuit. It appeared that the servo FETs were connected to +/-VCC. I'll check again later tonight.

Before you go with the Hitec servos, you should check out the Futaba 3103/3107/3108 servos. Very similar in price and I've been very happy with their quality, performance and durability.

BitHed
03-22-2005, 03:22 PM
...Fellas thats exactly what i needed to hear :) But i couldnt find a FUTABA ESC that went to 9.6...Not yet anyway...What else should i be looking at in the way of 9.6 options? Once we get some more I will start building som different lists up and make them sticky so we dont have to keep going through this...Sound good?

ruf4play
03-22-2005, 04:06 PM
For the H8? I would just run KO VFS1 or GM SX9 if I wanted to run 8-10 cells. I don't know if the Xray speedo would support it. Even so the "beefy" one is fwd only. Awesome package size and shape though.

RURC
03-24-2005, 04:02 AM
...Fellas thats exactly what i needed to hear :) But i couldnt find a FUTABA ESC that went to 9.6...Not yet anyway...What else should i be looking at in the way of 9.6 options? Once we get some more I will start building som different lists up and make them sticky so we dont have to keep going through this...Sound good?

Bit the only ESC i know that are for the voltage are ones for flyers.

BitHed
03-24-2005, 04:05 AM
For the H8? I would just run KO VFS1 or GM SX9 if I wanted to run 8-10 cells. I don't know if the Xray speedo would support it. Even so the "beefy" one is fwd only. Awesome package size and shape though.

Ruf the KO will work? I dint think it was ok for 9.6...There is a NOVAK one wich looks good...One for the bigger trucks which are coming out...unfortunately all MY money is tied up in looking after supplies for YOU guys...What is wrong with this picture? lol...

ruf4play
03-24-2005, 02:11 PM
Rats. The KO is only rated up to 8.4V.

I would go with GM then. If you need reverse, the new SX3R and SX6R will both take up to 12V and only run about $70-100 iirc.

BitHed
03-24-2005, 02:16 PM
...ruf i am seriously leaning more towards domething from the fly-boy section...They are using big loads without batting an eyelid...considering that MUCH of the 18 scale is based around plane-sized stuff anyway...and castle creations is originally air stuff...

ruf4play
03-24-2005, 04:19 PM
The problem with air stuff is that they haven't figured out the car stuff. Sure they can handle power, but their delivery feels funny and their braking is sketchy at best. I've run air controllers on smaller stuff, but they really do lack the feel of a high-end car esc.

alfreddajero
03-25-2005, 03:48 AM
This is for the people that are going to get rid of the stock electronics....you wont need to worry about the RX and Servo getting there 5-6 voltage input from the reciever....the RX will do that for you...And as for the ESC that will handle that voltage the GM's V3r or V4r and up will handle it with no probs and also the Mtroniks esc will handle all the input and there water proof what more can you ask for. And what makes a good ESC is the drive frequency or Pulse Frequency....the higher the hz (hertz) the better the throttle responce and smoothness of acceleration... :D

halfEIGHT
03-29-2005, 06:18 PM
...well well well...Look what the cat dragged in...Captain Bit are you sure you can keep us with us car fellas? We would'nt want you to get the wind taken out of your sails...Glad to have you here all the way from the Long White Cloud ;)

Whoa! The Captain Bit! Cool! :)