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HBC-series V7 LV+MV

Some of Protective and Safety mechanisms of TMM

controllers

Controllers mask interference and signal losses for

up to defined time in parameters. Motor revolutions are gradually reduced for longer

lasting signal drop outs or interference. When the signal is restored, the controller goes smoothly back to the required power. Long lasting
signal drop out (or its absence) is indicated by LED.

Engine does not start,

if the controller does not have the correct control signal. It also does not start after turn-on until the joystick is not in the

"engine off", i.e. in the neutral position (except for the "fast" or "immediate" start).

Temperature fuse of the controller is set to ca 100°C

Current fuses of the controller

have the task of limiting currents at current overload controller.

Monitor voltage circuits

are responsible for disconnecting the motor in right moment (or reducing engine power) if the battery is discharged

(or overdischarged), as in the case of lithium batteries is usually damaged. It can be advantageously combined with check voltage of each
cell (a separate external module connected to the ICS-2 connector).

Advantages of these mechanisms for TMM

controllers:

1) Thanks to the use of the automatic current fuse (

ACF

) the possibility of current overload of controller, motor and accumulators (and their

possible damage) even at crisis points is significantly reduced - controller disconnects the motor.

2) the used system of intelligent power reduce (

IPR)

always ensures through measurements of voltage, currents, accumulator condition and

calculations an optimal point of starting continuous reduction of motor performance (or the point when motor is switched off, according to
the setting), so that the accumulator cells do not get extremely discharged

– which is very important specially for Lipol cells. This, not men-

tioning other advantages, reduces the possibility of reversal of poles of lower cells (applies mainly to NiCd / NiMH cells).

3) the automatic current reduce (ACR) does not allow voltage drop below the threshold voltage of controller under extremely high current load.

When switching the motor off (reducing power) at a solid boundary as it is with standard controllers

(chart a)

it is not possible to determine the

amount of energy which is kept in the controller after the motor is switched off. It strongly depends on currents and inner resistance of the bat-
tery. The better the cells (harder) you have and the smaller the instantaneous current, the less energy (= time) remains for landing after the
motor is switched off by the controller. On the other hand, the worse the cells and the higher the instantaneous currents, the more energy re-
main

– but you do not know how much energy exactly.

Comparing to this,

TMM

controllers

(

chart b

) ensures that the remaining energy (after the motor is switched off by the controller) is practical-

ly independent on currents and inner resistance of the battery and it is possible to change its amount for some types of controllers according to
one's needs (higher for gliders, etc.). From the motor operation time view it is usually an insignificant amount of energy, the motor power would
decrease very fast anyway.

Switching-off voltage:

Thanks to the above described mechanisms, the switching

—off voltage (always meant as switching-off voltage per cell !) of

TMM

controllers is

independent on the amount of drawn current and the inner resistance of the battery. For each type of cells, switching-off
voltage is preset ( A123 to 2.5V, Lipol to 3.2V etc).

The controllers also feature possibility to set universal switching-off voltage

for exist-

ing types of cells and even for those that do not exist today,

UNI.

This voltage range is 0.1

– 60.0 V/cell.

Development, manufacture,

service:

Tel.: +420 577

001

350

MGM

COMPRO

, Ing. G. Dvorský

E-mail: mgm

mgm-compro.cz

Sv. Čecha 593, 760 01 Zlín, Czech Republic

Info: www.mgm-compro.com

Regular controllers (even Lipol compatible) have either a solid switch-
ing off voltage (for example 3V per cell) or it is possible to set this
value. For example for set boundary 3V per cell the controller is
switch off or it starts to reduce revolutions when this value is reached
no matter how big the drawn current is.

This means that the residu-

al energy significantly changes according to a instantaneous
current load of batteries

(and also according to inner resistance of

the cells] from 0 to 95 % - depending only on the set voltage bounda-
ry. If the example on the graph above is considered with a set
boundary of 3V per cell the controller will switch off when drawn cur-
rent is 20C when there is still 40% of energy still left, while for 5C cur-
rent when only 5% of energy is left. For boundary of 3.3V per cell the
controller would switch off for currents of 20C when only few percent
of energy were consumed while for 5C after 92% of energy would be
consumed.

TMM

controllers

handle the situation quite differently. The switching off

voltage is always recalculated into „inner“ voltage of the battery – therefore
is independent on both drawn current as well as inner resistance of the
accumulator.

This means the set residual energy is always the same

and does not depend on currents and inner resistance of battery.

Batteries  are  then  always  discharged  to  same  level,  regardless  how  big
currents are drawn. The value of set residual energy is therefore only little
dependent on the features of battery and the discharging current. For ex-
ample for switching voltage 3.7V per cell controller switches off the motor
or  starts  to  reduce  revolutions  always  after  90%  of  energy  is  used  up  no
matter if the drawn current is 20C or 5C.
(The  voltage  of  accumulator  after  switch  of  the  current  always  rises  to  a
value  close  to  curve  of  0.5V

– this discharging curve is close to „inner“

voltage of battery. This curve describes how much the controller is dis-
charged.

3.3V

cell (9.9V)

3.0V

cell (9.0V)

(12.6V)

60%

80%

0.5C 2C

2.7V

cell (8.1V)