Which h-bridge should I use to drive a dc motor 27v 3a

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1

Hi,

Do you have suggestions about which h-bridge should I use to drive a DC motor 27v 3A using Arduino/PWM?

I did som research and I could only found this two (affordable price):

l298:
This guy is very famous, but it supports only 2A max current. Moreover, I found I can use it in a parallel configuration to drive only one motor using a higher current, but I could not find anything about how to implement this configuration, and I also found it has a big voltage drop between vcc and its motor output jack, so it is not a reliable alternative.

Vnh2sp30:
This guy can support 30a max current, but only 16v max voltage.

Thank you

2

For the L298, see figure 7 in the (ST) datasheet. Hope I don't infringe on copyrights with below image.

L298_parallel.2.jpg
L298_parallel.2.jpg886×572 32.4 KB

No advise on alternative H-bridges, just don't know.

If you only need the motor to run one way, consider a single mosfet.

3

Nether of those is recommended maybe the newer

But that has a 24V limit. But look round that site for a motor driver that meets your needs.

4

The Pololu selection is high quality, well supported and the widest available to hobbyists, consult this table.

The motor driver must be able to handle the stall current of the motor, which is typically 5 to 10 times the running current. What is the stall current? Please post a link to the product page or motor data sheet.

5

The L298 is an older BJT design; significant losses. Go for a MOSFET type, far more efficient and less power losses (less heat to deal with).

A quick Google search turned up the MC33932 - can handle 5A peaks, which is probably not enough for your motors: I assume that 3A is running current, not stall current, meaning stall current can be 10A or even more!

6

Thank you all for the help.

I was looking for information about the motor, and I found it:

It is a Maxon 273759 precision brush motor (90 Watts) operating at 27 V max.

The motor offers a peak current of 3 A, with a maximum continuous current of 1.2 A.

So I may be able to go with the L298 or MC33932?

7

So I may be able to go with the L298

Please don’t, it is not so good and will get very hot.

The motor offers a peak current of 3 A

Peak current is not stall current. See if you have a winding resistance figure for the motor and use ohms law to calculate the stall current.

8

The motor offers a peak current of 3 A

What is the stall current?

9

The stall current is the current the motor pulls with the rotor locked immobile. Its simply the supply
voltage divided by the DC resistance or the motor.

Whenever the motor is started it begins by pulling that much current until the rotor speeds up and
motional back-EMF can build up to counter the supply voltage. The motor drive circuit has to be
able to handle the stall current (momentarily at least, preferably continuously).

A motor with a full load current of 3A might have 15 to 30A of stall current, note.

Most motors will cook quickly if operated continuously at stall, as the heat dissipation is hugely
greater than normal duty, so its normal to calculate it from the resistance, not try to lock the rotor
and measure it directly.

10

Having found the datasheet for the 273759 Maxon motor turns out it tells you all you need to
know:

48V, 0.93A nominal, ie about 40W, not 90W.
Stall current 4.21A, winding resistance 11.4 ohms.
nominal speed 2990rpm @ 48V, nominal 0.11Nm torque @ 0.93A

No idea where the 27V 3A 1.2A figures come from - have you got the right part number?

BTW its advised to post links for each piece of hardware you refer to up front.