Electronics > Beginners

555 Motor Speed Controller

<< < (5/8) > >>

Bulb:
I recommend of using snubber now, for this situation 5A and 12V.

If is possible, can you measure voltage waveform across MOSFET drain source electrodes?

Do you plan of using this type of load for always? In your first post you mention proxxon drill. Motor of drill has its own inductance, is it same as one used in test (measurments)?

Probably this will work without snubber because IRF630 can work up to 200V, but to be safe, I recommend of using snubber.

For the first test you can use snubber with R around 10 ohms / 2W and capacitor of 4.7uF (working voltage over 16V, around 25V).
RC snubber connect parallel to (with) flyback diode.

mike_mike:

--- Quote from: Bulb on April 23, 2019, 08:26:21 pm ---If is possible, can you measure voltage waveform across MOSFET drain source electrodes?

Do you plan of using this type of load for always? In your first post you mention proxxon drill. Motor of drill has its own inductance, is it same as one used in test (measurments)?

--- End quote ---
I will measure tomorrow (today it is too late) the voltage waveform across MOSFET D-S.

I will use only PCB drills with this PWM controller. I will start by using the proxxon, but I am planning to use some other drills. I do not know the inductance of the motor, and it is not with the one used in measurements.

The 4.7uF capacitor needs to be upolarised or needs to be polarised ?

Bulb:
Capacitor need to be nonpolarised, for example ceramic capacitor https://en.m.wikipedia.org/wiki/Ceramic_capacitor

Ok, I think that RC snubber with asumed values can help, because snubber will conduct until diode turns on.

mike_mike:
I searched for 4.7uF unpolarised capacitor at the local electronics shop and in my boxes, but I did not find any 4.7uF capacitor.
I cannot order only a few 4.7uF capacitors from the internet...
I there any other solution ?
I will also try a simulation in LTSpice.

Bulb:
You can also try with 1uF, 3.3uF, 2.2uF or 6.8uF. Any of these values should help. You can also make a parallel of 2.2uF and get about 4.4uF.
The use of the RC snubber in this particular case is to reduce the surges (voltage spikes) and prevent the possible destruction of the MOSFET.

Navigation

[0] Message Index

[#] Next page

[*] Previous page

There was an error while thanking
Thanking...
Go to full version
Powered by SMFPacks Advanced Attachments Uploader Mod