The Hobbyking Brushless series use low drain brushless motors for extended motor life and therefore reliability, HV operating voltages also mean this servo can operate directly from a 2s Lipoly Battery, eliminating the need for voltage reduction devices like UBECs and Regulators.
Specs: Voltage: 6.0v / 7.4v Speed: 0.07sec/60deg (6.0v) - 0.06sec/60deg (7.4v) Torque: 5.0kg.cm (6.0v) - 6.0kg.cm (7.4v) Size: 40mm x 20mm x 37.5mm Weight: 56g Gear Train: Full Titanium Alloy Motor: Brushless Casing: alloy heatsink Centre Ball Bearing: 3 Lead: 300mm HD with Universal/JR Plug
I had 4 of those 7,4V servos, so called HV. Tested in my model with a stored Lipo 2S.
Everything worked just fine. Then, before going to fly I charged may 2S Lipo. I switched on my model and all 4 Servos burnt immediately. So why do the not tell us, that 7,4 is a limit that you may not come over. A fully charged Lipo 2S has 8,4V. Thats the voltage HV should be able to withstand. 7,4 V does absolutely make no sense. With 8,4V on a 2S I burnt 170$ just by switching on. And a stored Lipo with a 7,4V max. does not have half of its full capacity.
Yes, but in the description they say, that it can be operated directly from 2S LiPo which is definitely not the truth. They do not say that you have to charge your LiPo to only less than the storage voltage. It does not make sense to call a servo HV when only able to operate at 7,4V but not at 8,4V. Only a 8,4V servo is truly able to be operated diretly from 2S LiPo. And in my opinion, only a 8,4V servo should be called HV.
I am asking how many people have destroyed their HV servos with a 2S LiPo. There are some that die immediately, and others where peole say they get very very hot and so will not last very long. A lot of people recommend 6V operation for a kot of HV servos. I saw specs that state 8,4, but is very seldom. So I think HV is not HV, there are differences.
Sistema de Controle: PWM controle por largura de pulso
Processador: IC Digital
Pulso necessá*rio: 3-5 Peak V para pico da onda quadrada
Trabalhando freqü*ê*ncia: 1500 mS / 333 Hz
Sensor de â*ngulo de rotaç*ã*o: Potenciô*metro de precisã*o
Rotaç*ã*o: Marcha à* esquerda: 46, Rotaç*ã*o para a direita: 46
Tensã*o: 4.5V a 7.4V
Faixa de temperatura: -20 ℃* a 60 ℃*
Tipo de Driver: MOSFET
Â*ngulo de funcionamento: 45 °*. um pulso viajando lado 400μ*s
Direç*ã*o: No sentido horá*rio, Pulso / Viajando 900μ*s-2100μ*s
Pulso Â*mbito Largura: 900-2100μ*s
Pulso Neutro: 1500μ*s
Velocidade: (sem carga): 0.07sec / 60 °* * 6.0V
0.06sec / 60 °* * 7.4V
Torque: (load Full Stall): 5.00 kg. cm*6.0V
6,00 kg. cm*7.4V
Corrente em repouso: <0,05 A / 6.0V <0,05 A / 7,4 V
Correndo atual: <0,10 A / 6.0V <0,20 A / 7,4 V
Stall atual: 1.5 A 6.0V / 2.2 A / 7.4V
Tipo de Motor: Brushless Motor
Rolamentos: 3 Ball Bearing
Tendo Tipo: MR74 (4mmX7mmX2mm)
Materiais Gear: Titanium da engrenagem
Caso Servo: (Radiador de alumí*nio) Centro de metal
Plug: "J" tipo
Comprimento do fio conector: 300,00 milí*metros
Fio Conector SPEC: OD1.4mm/60 x 0,08 milí*metros 3p x "J" 300 milí*metros tipo
Peso: 56,00 g
Dimensõ*es (L x W x H): 40,00 * 20,00 * 37,50 milí*metros
You already stated the neutral pulse-width in the specs. I'm looking for the dead band spec. A truly great quality digital servo should have a dead band at 1μ*s or less. For use in the current generation of eCCPM helicopters using flybarless control systems, a small dead band is beneficial to the performance of the heli. THKS!
i don't think this servo have enough power for 700 size. they need at least 12kg for 3d flying, and 15kg for hard 3d.
good luck, and remember to run the power wire ( ,-) on different set of wire in case of burn out :)
This servo is perfectly OK for '700' heli tail rotor use. Be aware that this servo does not have the usual 760uS neutral of most servos designed for tail control use. Neutral is 1500uS.
I received this and the higher torque HK82810 servos today. Deadband for all is a 'wide' 3uS. Not happy...
1 thumbs up!
Received one of these servos today (May 4, '12) and performed a little bench testing on 2S LiPo, fully charged. Overall the BL-89601 works OK but there are four things that I'm going to mention here.
First, if this servo is going to be installed in a heli as a tail servo, the deadband is greater than optimum, @3uS vs 1uS or less.
Second, with no load, just working the servo moderately fast with the transmitter stick, it doesn't take more than a few seconds before heat is noticed in the metal case center section. It's good that the motor's heat is brought outside to be dissipated efficiently but why, with the claim of "...low drain brushless motors..." is so much heat being generated? How much hotter will it get when doing real work?
Third, if the servo is moved at a 'moderate' speed, there's a chattering sound created from the combination of the solid, all-metal gear train and some characteristic of the brushless motor controller working together. I wouldn't say this is any indication of a problem but the coarse sound is impossible to ignore.
Fourth, with no input to change position commanded, the servo like to hunt or chatter a little. This is something within the servo, not from it responding to unsteady input signals. Clearly if the deadband was tighter this chattering would be far worse.
I opened the servo case to see the internal build quality and was very please
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This is an update to the long-winded review I made for the BL-89601 servo yesterday. With only a few minutes of bench testing (on 2S LiPo power, Spektrum AR600 receiver), this servo has developed a very serious hesitation issue. Sometimes it will "stick" and not move (under a command to move) unless I push on the output arm. Its actions perfectly mimic a brushed-motor servo with worn/dirty brushes/commutator. Sometimes when 'stuck', the quiescent current would spike up to .50A from a normal resting current of .07A, allowing heat to be noticed in the case. Nudging the arm would "unstick" the motor and the current would drop back to the idle state. If I could guess, I'd say there's a bad Hall-effect sensor in the motor circuit and correct rotor motion can't be determined. There's forty one dollars down the drain :-( I've derated the score for this servo. 1 Crown for overall rating, 1 Crown for value but must admit the quality is still worthy of a four.
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When I received BL 89601 servo I really have a good feeling about it. Smooth movement no slope aluminum middle part. I want to check it, so I open it. Gear part is connected to the main part with 3 wires, and after a couple of moves, one of the contact fell of. Oh boy, that couldn’t last long. I was able to re solder that wire and I checked the other soldering spots, but seem that there was a better work. I’m using that servo on the 600 size helicopter for the tail. It works on 6V and it works very well. This is my first servo for the tail, on that size of the helicopter, which works absolutely cool. I tried also the MI digital HK 47902 TM-HV on the same helicopter and I have to say that this servo works even better, but after the flight it is a little warm.
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ATENCION ! NO USEN ESTE SERVO EL LA COLA DE UN HELICOPTERO . el servo no es malo, pero produce oscilaciones en la cola del heli ,como lo explica en el comentario el usuario SMPRC.
ATTENTION! DO NOT USE THIS SERVO THE TAIL OF A HELICOPTER. the servo is not bad, but produces oscillations in the tail of the heli, as user SMPRC explains in the comments.
I put it on a G4 Raptor and I had to change it, tail ranged almost permanently due to the servo.