Questions tagged [commutation]
The commutation tag has no usage guidance.
29
questions
0
votes
1answer
22 views
Commutation and Triggering Angle
I have circuit to analyze like that
L = 5mH
Vs = 230V (RMS)
Iload = 10A Constant
Vda = 100V
I should calculate commutation(u) and triggering angle but not known both. I tried to find both by ...
0
votes
0answers
34 views
BLDC does not start on its own using trapezoidal commutation
I am trying to control a brushless motor using trapezoidal commutation. I read the signals from the Hall sensors and switch the FETs of each motor phase accordingly. I run the commutation task at 1KHz....
0
votes
0answers
30 views
BLDC Motor Hall Sensor Response
I'm currently developing a BLDC controller with hall sensors, curious about where the hall sensors triggered. Are they triggered when just a commutation axis becomes or around the axis (at the sector ...
0
votes
1answer
40 views
BLDC Y-shaped motor with Hall sensors generating different combination of back EMF on windings with different direction?
I have a BLDC Y-shaped motor. I connected the Hall sensors and winding to a logic analyzer to see the combination of back EMF on thr windings. My intention is to eventually create a commutation table ...
1
vote
1answer
82 views
Confusion in magnetic neutral plane of DC machine
I was reading book Electric Machinery by Chapman and in topic 'Armature reaction ' It is written that
"The magnetic neutral plane is defined as the plane within the machine where the velocity of ...
1
vote
2answers
146 views
Why do I need two PNP BJTs as a switch rather than only one?
As far as I know, the circuit into the read circle works as a switch. I would like you to help me to understand how does the circuit works as a switch and why I need something so complicated instead ...
1
vote
0answers
19 views
How to pick the most convenient mosfets for comparing switching capabilities and understanding SPICE2 simulation models?
I have picked BS170 (signal application n mosfet) and IRFZ44n (power application n mosfet). I will tell the professor my decision is based on the fact that they both have very different power ...
1
vote
4answers
89 views
How to make an audio 5.1 switch?
I'd like to make a 5.1 audio switch to enable my 5.1 audio system (+mic+headphones) to be available for any of the 4 computers it can be connected to.
So I guess I would have :
INPUT : 4 (computers) ...
0
votes
0answers
35 views
lyapunov function derevation
hi could you please help me to know how did they find the derivative of V lyapunov function
1
vote
1answer
64 views
What is the effect of no-current periods in commutation on output power of a PM DC motor?
I have made a PM DC motor. This motor works on a unique magnetic circuit. This motor can work very well at different input levels. When it uses an input of 5.915 volts*3.5 Amperes=20.7025 Watts, its ...
0
votes
1answer
33 views
Sanity check for max motor torque
A KDE brushless DC motor has:
Kt = 0.0189 N*m/A (Kv = 505 rpm/V)
R = 7 mΩ
voltage range of about 30-60 VDC
Specsheet link
Assume the motor is
connected to 30 VDC input
ideal, sensored, six-step ...
1
vote
2answers
58 views
PMDC motor: how much is voltage reduced if the resistance produced by commutation system is eliminated?
I have made a PMDC motor. The resistance of the coils is 0.25 ohms. But the commutation system is very resistant. It adds more 0.85 ohms to the armature resistance. So, the total resistance becomes 1....
0
votes
1answer
106 views
BLDC commutation
I have some dilema with commutation on BLDC motor. I have driver for BLDC (MP6540) and I can commutate BLDC motor but motor it is heating up and speed is not appropriate (datasheet says that motor ...
2
votes
1answer
239 views
BLDC motor drive: Requires an external push to start rotating
I am trying to drive a 23-pole pair(i.e. 46 poles) BLDC motor using an LV8139 pre-drive, the output of which is fed to drive the 3 half bridge MOSFETs. I managed to connect the correct phase sequence(...
1
vote
1answer
1k views
Why do the polarities of the capacitor change while discharging?
I was going through the working of class D commutation and the article said:
As soon as the capacitor completely discharges, its polarities will be reversed but due to the presence of diode the ...
0
votes
2answers
647 views
What factors affect a thyristor's “circuit commutated turn-off time”?
In datasheets, they give this value at a certain operation point (voltage, current, and di/dt). My question is... What are the effects of changing these parameters.
For example, if di/dt is ...
1
vote
0answers
34 views
Is zero loss turn-off possible for thyristors?
Consider this very basic circuit:
simulate this circuit – Schematic created using CircuitLab
Don't mind the values - they don't matter, as this question is conceptual.
Imagine that Vcomm is ...
0
votes
2answers
83 views
Looking for reed relays for high voltage commutation
I need to chose a reed relay for connecting a point to high voltage (probably between 7000V:15000V) or to GND signals.
System will have 8 channels (pins). Some of 8 pins will be connected to high ...
1
vote
3answers
114 views
Where exactly appears the channel capacitance and Ron when switch on DG442 switches
I have this switch in a circuit, actually there is 30 switches.
https://www.vishay.com/docs/70053/dg441.pdf
When system is not executing any operation, switches are off. Sx and Dx are not connected. ...
2
votes
1answer
197 views
SSRs influenced by physical proximity?
This is part of a two-head EVSE. The two solid-state relays are used to drive contactors that supply high current power to the vehicles. I used to use a MOC3040 based triac circuit for this job, but ...
0
votes
0answers
108 views
Commutation techniques in SCR
I read in a textbook that "Commutation Time is more in Current Commutation compared to Voltage Commutation".Kindly Elaborate.
-2
votes
1answer
69 views
Newbie question: Feasible way of amplifying 100+ channels of slow and low amplitude signal
I want to amplify signal coming in hundreds of channels (sensor array each producing a very low amplitude 30-200Hz signal). For every channel i care only about intensity of the signal (i don't need ...
0
votes
1answer
3k views
BLDC Motor rotor vibrates with audible high pitch beep, but does not spin. Controlled by custom motor controller
The circuit I have built (taken from the HIP4086A gate driver data sheet found at https://www.intersil.com/content/dam/intersil/documents/hip4/hip4086-a.pdf) is:
The only difference between this ...
2
votes
1answer
240 views
LTspice diode commutation
I have modeled an ideal diode rectifier fed from a 230V/50Hz grid with a slim DC link capacitor and a constant power load (1kW) coupled with a small resistive load. For Cdc=14uF i get a phase input ...
0
votes
0answers
61 views
Commutation overlap symmetry
Let's say we have three phase diode (ignore SCR in the picture) rectifier:
With no source inductance, diodes are conducting at following angles:
Diode 1: 30º < X < 150º
Diode 4: 210º < X &...
0
votes
1answer
50 views
How did rotary converter commutators conduct electricity?
I've been reading about rotary converters and examining photographs, but I've noticed that nearly all have a very strange (to me) commutator design. It looks like a piece of wire screen rather than ...
-1
votes
1answer
72 views
Quick specific questions about Electric Motors that I can't find on Internet
I want to talk about induction motors and Universal motors.
1) is the rotor of an Universal Motor a Wound rotor?
2) the induction motor with Wound rotor have commutators?
3) Universal Motor can ...
2
votes
2answers
2k views
Brushless DC motor problems at high velocities
For a project we use a brushless DC (BLDC) motor. Everything works fine until we tried to reach high velocities. I will first explain my setup, and than explain our problems using some graphs. ...
14
votes
4answers
2k views
H-Bridge Fly-Back
Sorry if this question is a little long, but I though it prudent here to discuss the state-of-the art as I know it before asking the question.
ISSUE
When using an H-bridge to drive a bidirectional ...
