Showing posts with label motorcycle. Show all posts
Showing posts with label motorcycle. Show all posts
Saturday, November 5, 2016
Motorcycle Shunt Regulator Circuit using SCR
Motorcycle Shunt Regulator Circuit using SCR
The circuit presented here is a Rectifier plus Regulator for a 3-Phase charging system of Motorcycles. The rectifier is full-wave and the regulator is shunt-type regulator.
By: Abu Hafss
A motorcycles charging system is different from that on cars. The voltage alternator or generator on cars are electro-magnet type which are quite easy to regulate. Whereas, the generators on motorcycles are permanent magnet type. The voltage output of an alternator is directly proportional to the RPM i.e. at high RPM the alternator will produce high voltages more than 50V hence, a regulator becomes essential to protect the entire electrical system and the battery too.
Some small bikes and 3-wheelers which do not run at high speeds, only have 6 diodes (D6-D11) to perform full-wave rectification. They dont need regulation but those diodes are high ampere rated and dissipate a lot of heat during operation.
In bikes with proper regulated charging systems, normally shunt-type regulation is used. This is done by shorting out the alternators windings for one cycle of the AC waveform. An SCR or sometimes a transistor is used as shunting device in each phase.
For the rectifier, there are three options:
a) Six automotive diodes
b) One 3-phase rectifier
c) Two bridge rectifiers
All must be rated at least 15A and heat-sinked.
The automotive diodes are two types positive body or negative body hence, should be used accordingly. But they might be little difficult to contact to heat-sink.
If using two bridge rectifiers, they may be used as shown.
By: Abu Hafss
A motorcycles charging system is different from that on cars. The voltage alternator or generator on cars are electro-magnet type which are quite easy to regulate. Whereas, the generators on motorcycles are permanent magnet type. The voltage output of an alternator is directly proportional to the RPM i.e. at high RPM the alternator will produce high voltages more than 50V hence, a regulator becomes essential to protect the entire electrical system and the battery too.
Some small bikes and 3-wheelers which do not run at high speeds, only have 6 diodes (D6-D11) to perform full-wave rectification. They dont need regulation but those diodes are high ampere rated and dissipate a lot of heat during operation.
In bikes with proper regulated charging systems, normally shunt-type regulation is used. This is done by shorting out the alternators windings for one cycle of the AC waveform. An SCR or sometimes a transistor is used as shunting device in each phase.
The network C1, R1, R2, ZD1, D1 and D2 forms the voltage detection circuit, and it is designed to trigger at about 14.4 volts. As soon as charging system passes this threshold voltage, T1 starts conducting. This sends current to each gate of the three SCRs S1, S2 and S3, via current limiting resistors R3, R5 and R7. D3, D4 and D5 are important to isolate the gates from each other. R4, R6 and R8 help in draining any possible leakage from T1. S1, S2 & S3 should be heat-sinked and isolated from each other using mica insulator, if using common heat-sink.
For the rectifier, there are three options:
a) Six automotive diodes
b) One 3-phase rectifier
c) Two bridge rectifiers
All must be rated at least 15A and heat-sinked.
The automotive diodes are two types positive body or negative body hence, should be used accordingly. But they might be little difficult to contact to heat-sink.
If using two bridge rectifiers, they may be used as shown.
  |
| Bridge Rectifier |
 |
| Automotive diodes |
 |
| 3-phase rectifier |
 |
| Bridge Rectifier |
Available link for download
Saturday, October 8, 2016
Motorcycle Accident Alarm Circuit
Motorcycle Accident Alarm Circuit
In this post we learn how to make an useful motorcycle accident alarm circuit for sending alarm signal to the distant population in an event of an accident, especially if it happens in a relatively lonely area. The idea was requested by Mr. Rayan Dsouza.
The Request
Sir..!!
I want a circuit..!! That has a buzzer in it. This buzzer activates only when the motorcycle has undergone a accident..!! That is, the buzzer should get activated when accident of a motorcycle takes place. So that the people can be aware of that accident. Sir can u help me..!! Plz sir.. Can u make a circuit for this..!! Its urgent sir..!!
The Design
A simple motorcycle accident alarm circuit can be built at home with the help of the design shown in the above figure.
The circuit is made up of two stages, the tilt sensor, and the delay ON alarm stage.
The sensor can be seen at the left side of the design, consisting of a plastic ball, a small spherical neodymium magnet and a reed switch.
The magnet is inserted into the plastic through a temporary hole made at the top, which is later on sealed with epoxy glue.
On the outer side of the ball, a reed relay switch is glued such that the magnet and the reed lie side by side with only the ball plastic separating them.
The above situation is supposed to keep the reed relay switched ON as long as the ball is not tilted and the magnet inside is vertically still in the shown specified position.
The reed relay output can be seen integrated with a delay On relay timer circuit comprising a couple of BJTs and the associated resistors and capacitors.
In the normal situations, while the reed relay is in the activated position, the base of T1 is held grounded and the delay ON timer is unable to react, and remains in a dormant condition.
The sensor unit along with the circuit is supposed to be fixed in the bike such that as long as the bike is in its vertically standing position, the magnet maintains its position around the bottom center of the ball.
However in an event of an accident, when the motorcycle could be in a tilted situation the magnet would roll and be displaced from the specified position allowing the reed switch to open.
As soon as the reed relay opens, C2 begins charging and the delay circuit begins counting.
Depending on the values of C2 and R2 (which could be set for 5 seconds delay), C2 charges fully and triggers T1 into conduction.
This in turn switches ON T2 and the relay, sounding the alarm, and informing the people around regarding the mishap.
The alarm is stopped as soon as the motorcycle is lifted on its upright position or the battery power is disconnected.
The Request
Sir..!!
I want a circuit..!! That has a buzzer in it. This buzzer activates only when the motorcycle has undergone a accident..!! That is, the buzzer should get activated when accident of a motorcycle takes place. So that the people can be aware of that accident. Sir can u help me..!! Plz sir.. Can u make a circuit for this..!! Its urgent sir..!!
The Design
A simple motorcycle accident alarm circuit can be built at home with the help of the design shown in the above figure.
The circuit is made up of two stages, the tilt sensor, and the delay ON alarm stage.
The sensor can be seen at the left side of the design, consisting of a plastic ball, a small spherical neodymium magnet and a reed switch.
The magnet is inserted into the plastic through a temporary hole made at the top, which is later on sealed with epoxy glue.
On the outer side of the ball, a reed relay switch is glued such that the magnet and the reed lie side by side with only the ball plastic separating them.
The above situation is supposed to keep the reed relay switched ON as long as the ball is not tilted and the magnet inside is vertically still in the shown specified position.
The reed relay output can be seen integrated with a delay On relay timer circuit comprising a couple of BJTs and the associated resistors and capacitors.
In the normal situations, while the reed relay is in the activated position, the base of T1 is held grounded and the delay ON timer is unable to react, and remains in a dormant condition.
The sensor unit along with the circuit is supposed to be fixed in the bike such that as long as the bike is in its vertically standing position, the magnet maintains its position around the bottom center of the ball.
However in an event of an accident, when the motorcycle could be in a tilted situation the magnet would roll and be displaced from the specified position allowing the reed switch to open.
As soon as the reed relay opens, C2 begins charging and the delay circuit begins counting.
Depending on the values of C2 and R2 (which could be set for 5 seconds delay), C2 charges fully and triggers T1 into conduction.
This in turn switches ON T2 and the relay, sounding the alarm, and informing the people around regarding the mishap.
The alarm is stopped as soon as the motorcycle is lifted on its upright position or the battery power is disconnected.
Available link for download
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