Questions tagged [commutation]

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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 ...
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4answers
64 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) ...
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0answers
33 views

lyapunov function derevation

hi could you please help me to know how did they find the derivative of V lyapunov function
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1answer
61 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 ...
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1answer
29 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 ...
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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....
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1answer
72 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
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1answer
159 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(...
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1answer
643 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 ...
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2answers
238 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 ...
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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 ...
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2answers
77 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 ...
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3answers
102 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. ...
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1answer
185 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 ...
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0answers
101 views

Commutation techniques in SCR

I read in a textbook that "Commutation Time is more in Current Commutation compared to Voltage Commutation".Kindly Elaborate.
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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 ...
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1answer
2k 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
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1answer
201 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 ...
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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 &...
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1answer
49 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 ...
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1answer
70 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 ...
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2answers
1k 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. ...
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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 ...