Questions tagged [commutation]

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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 ...
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1answer
77 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
249 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
146 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
33 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
74 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
92 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
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1answer
170 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
100 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
999 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
180 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
58 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
48 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 ...