Wiring A Brunswick A2 Motor Start Relay

Wiring a Brunswick A2 motor start relay involves a process that is important to understand to ensure the optimal performance of the machine. While the specific steps for this particular model are not readily available, the general process of wiring a starter relay involves a set of connections and terminals. This includes the battery (B), start (S), and motor (M) terminals, which play a crucial role in sending voltage to the S terminal and energizing the solenoid's electromagnetic windings. The solenoid, in turn, generates horsepower for a limited time. Additionally, the positive and negative cables link the starter solenoid and battery terminals, while the ground cable connects the engine cylinder block near the starter to the negative terminal. Understanding the wiring arrangement is essential for effective maintenance and troubleshooting of the Brunswick A2 motor start relay.

Understanding the starter and starting system

The starter motor is responsible for cranking the engine to get it going. It operates with the help of a solenoid, which generates a significant amount of horsepower for a limited time. The solenoid is usually mounted on top of the starter.

There are two common types of starters: direct-drive and gear-reduction. Both designs operate similarly. When the driver turns the ignition key to the "start" position, the solenoid engages a plunger, which acts on a lever fork inside the starter. The fork then pushes the starter's pinion gear into mesh with the ring gear on the engine's flywheel or flexplate.

The solenoid's plunger pushes a disc against a set of contacts, allowing current to flow from the battery to the starter. This current passes through the starter's insulated brushes, which ride on the commutator portion of the armature, before entering the field coils and the armature windings.

The current flowing through the field coils and armature creates a magnetic field that causes the armature to spin. The commutator continuously switches the polarity of the circuit to keep the armature spinning in the same direction.

In a direct-drive starter, the spinning armature turns the pinion gear directly. In a gear-reduction starter, the armature drives a set of gears that turn the pinion gear. The starter's pinion gear rotates the engine's flywheel, which is bolted to the crankshaft, setting the internal engine components (pistons, camshaft, etc.) in motion.

The starter relay is a small but crucial component of the starting system. It is often confused with the starter solenoid, but they are two different parts. The starter relay switches on the current that activates the starter solenoid. It is usually smaller in size and comprises a magnetic core with a wire wound around it. On one end of the core is an armature or plunger that closes the contacts to work as a switch.

The starter solenoid, on the other hand, is usually bigger and of heavier construction. It closes the switch for the starter motor and is usually mounted on the motor. It consists of two coils of wire and a magnetic core towards one end. The core is free to move in and out, with a return spring on one end. The starter solenoid also moves the pinion gear to engage the flywheel.

The starter relay is essential for the engine to start. It allows a large current to flow when you turn the ignition key or press the start button. The ignition switch cannot handle the high current required by the starter motor, so the relay acts as a remote switch that controls the high-current circuit.

The starter relay is typically located in the fuse box (also called the power box) or the fuse panel under the dash. It can also be found on the right fender, usually inside a long box with a black cover.

The starter relay consists of housing, coil windings, a magnetic core, and an armature or plunger. When you turn the ignition key to the "start" position, the "S" terminal (or 85 terminal in some relays) receives a 12-volt signal from the car's battery. A small current passes through the coil windings and to the ground. This creates a magnetic field that moves the armature, closing the contacts and completing the circuit to provide the starter solenoid with current from the battery.

When the engine has started, turning off the ignition deprives the starter relay coil of current, causing it to lose magnetism and releasing the armature. This opens the contacts and breaks the electric power in the starter circuit, stopping the motor.

How are starters wired?

A starter motor cranks the engine to get it going. Nearly all internal combustion-powered vehicles, except some hybrids, use a starter motor. The starter, which operates with the help of a solenoid, can generate a significant amount of horsepower for a limited time. On most vehicles, the solenoid is mounted on top of the starter.

A typical starter uses a solenoid to generate a specific amount of horsepower for a limited time. As you turn the ignition to the “start” position, voltage is sent to the S terminal, energizing the solenoid’s electromagnetic windings. The windings create a magnetic field that pushes a disc against the B and M contacts, producing an electrical connection that cranks the engine.

The positive cable links the starter solenoid to the positive battery terminal. Meanwhile, the negative or ground cable connects the transmission or engine cylinder block near the starter to the negative battery terminal.

There are two common types of starters: direct-drive and gear-reduction. Both designs operate in a similar manner. When the driver turns the ignition key to the “start” position, the solenoid engages a plunger, which, in turn, acts on a lever fork inside the starter. The fork then pushes the starter’s pinion gear into mesh with the ring gear on the engine’s flywheel or flexplate.

The solenoid’s plunger pushes a disc against a set of contacts. Current flows from the battery to the starter once the contacts connect. Current then passes through the starter’s insulated brushes, which ride on the commutator portion of the armature, before entering the field coils and the armature windings.

The current flowing through the field coils and armature creates a magnetic field that causes the armature to spin. The commutator continuously switches the polarity of the circuit to keep the armature spinning in the same direction.

If the starter has a direct drive, the spinning armature turns the pinion gear directly. If the starter has a gear drive, the armature drives a set of gears that turn the pinion gear. In either case, the starter’s pinion gear rotates the engine’s flywheel. Because the flywheel is bolted to the engine’s crankshaft, the internal engine components (i.e. pistons, camshaft, etc.) are set into motion.

When wiring a starter, incorrect wiring can cause a lack of power. If you’re moving to a bigger engine and bigger starter, you need to reconfigure the wiring to the starter. If you’re experiencing starter troubles with a new car or a bigger engine package, the wiring should be the first thing you check.

Most high-performance starters use two wires: the larger main wire and the smaller activation wire. The activation wire is attached to the switch that engages the starter. It’s the signal side of the ignition process. The activation side builds the coil inside the solenoid and pulls it. When the solenoid is pulled far enough, the bus bar in the back solenoid will move and pass power to the starter motor itself.

Direct-drive vs. gear-reduction starters

Direct-drive starters and gear-reduction starters are the two methods for driving the ring gear of a flex plate or flywheel. Direct-drive starters, the first to be introduced, use a large, low-speed motor to rotate a pinion gear in a 1:1 ratio with the armature shaft. On the other hand, gear-reduction starters, introduced by Chrysler in the 1960s, use smaller, faster motors to rotate their pinion gears in a roughly 4:1 ratio, resulting in lower power consumption and higher torque.

Direct-drive starters have a straightforward design where the motor armature and the Bendix drive are directly connected and positioned inline. They are typically cheaper than gear-reduction starters, but they require up to 50% more electrical power to turn over the engine, necessitating larger battery cables and components designed for higher current. Direct-drive starters are also larger and heavier than gear-reduction starters, and less efficient.

Gear-reduction starters, on the other hand, use gears to reduce the speed of a higher-speed electric motor to extract more torque at the flywheel end. There are two common designs: Offset Gear Reduction, where the motor armature and Bendix drive are not inline, and Planetary Gear Reduction, where they are. Gear-reduction starters are smaller, lighter, and more efficient than direct-drive starters, making them ideal for cold weather when cranking amperage drops. They also have better heat resistance due to the extra space around them. However, they tend to be more expensive and have a higher part count.

In summary, direct-drive starters are typically more cost-effective, while gear-reduction starters offer advantages in terms of size, weight, efficiency, and torque. When choosing between the two, it is essential to consider factors such as cost, torque-to-weight ratio, efficiency, and cranking ability in cold weather.

How a typical starting circuit works

A typical starting circuit is fairly straightforward. When the driver turns the key to the “start” position in a typical starting system, battery voltage flows from the ignition switch to an underhood relay. The ignition switch has a return spring, so that as soon as you release the key, it springs back and turns the starter switch off.

As long as the neutral safety switch is in the park position (or the clutch safety switch is closed), the relay closes, allowing voltage to flow to the starter solenoid. The solenoid then engages the starter to crank the engine.

The starter solenoid works as a powerful electric relay. When activated, through the control terminal, the solenoid closes the electric circuit and sends the battery power to the starter motor. At the same time, the starter solenoid pushes the starter gear forward to mesh with the ring gear of the engine flexplate or flywheel.

The starter motor itself has a device, called a Bendix gear, which engages its pinion with the gear ring on the flywheel only while the starter is turning the engine. It disengages as soon as the engine picks up speed.

The starter motor typically has four field windings (field coils) attached to the starter motor housing from the inside. The armature (the rotating part) is connected through the carbon brushes in series with the field coils. On the front end of the armature, there is a small gear that is attached to the armature through an overrunning clutch.

The starter motor cranks the engine to get it going. It draws power from the battery through thick cables that can channel high electric current. The positive cable links the starter solenoid to the (+) battery terminal. The negative or ground cable connects the transmission or engine cylinder block near the starter to the negative (-) battery terminal.

Starter solenoid terminals

A starter solenoid is a combination of a solenoid and switches, and it is one of the main components of a car starter motor. The starter solenoid has three or four terminals, depending on the model. The two thick terminals are copper bolts of 8mm or 10mm thickness, with one being the power supply terminal of the motor field winding, and the other connected to the car battery. The two thin terminals are pull-in terminals, with one being the solenoid terminal and the other directly connected to the shrapnel inside the motor.

The starter solenoid functions to control the start circuit on/off and to drive the starter pinion engaging in the flywheel ring gear. When the ignition switch is turned on, a small electric current is sent through the starter solenoid, which then closes a pair of heavy contacts, relaying a large electric current through the starter motor, setting the engine in motion.

The starter solenoid is usually mounted directly on top of the starter motor. The starter motor itself is bolted to the engine or transmission. The starter solenoid has one small connector for the starter control wire, and two large terminals: one for the positive battery cable, and the other for the thick wire that powers the starter motor. The starter solenoid works as a powerful electric relay, closing the electric circuit and sending battery power to the starter motor when activated through the control terminal.

When the ignition key is turned to the "Start" position, the engine computer checks if the ignition key security code matches. If it does, the starter relay is activated, closing the starter control circuit and activating the starter solenoid. The starter solenoid then closes the high-current circuit, sending power to the starter motor, and pushing the starter gear forward to mesh with the engine flexplate gear.

Frequently asked questions