F R switch question

skipsmith521

This question is really just for learning purposes...

Everyone always talks about upgrading the FR switch when doing upgrades...

I have a DCS cart... I have had to replace micro switch not too long ago. How does a DCS cart differ from PDS or series carts regarding the FR switch?

I have already read how the DCS reverse is not desirable and ezgo had issues or something like that...

Just want to learn more about the differences in carts.

Thx

Skip

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BGW

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scottyb

The DCS is a sepex drive.

Upgrading the F&R is for series carts.
In a series cart all the battery amperage to the motor travels through the F&R.

JohnnieB

You only have to upgrade the F/R switch on Series drive carts and there are more series drive carts out there than SepEx drive carts, so more people talk about upgrading the F/R switch.

The direction a cart motor spins is determined by the relative direction of current flow in the Armature and Field (aka Stator) windings. In a series drive, the same current that flows through the Armature also flows through the Field, so a mechanical switch with heavy (high amperage) contacts was used to change the direction of current flow in the Field windings to make the motor spin in the opposite direction. In a SepEx (Separately Excited) drive the current flow through the Field is separate from the current flow through the Armature and the amp flow in the Field is only about 1/10 of the amp flow in the Field and the direction of amp flow is controlled by the controller.

A SepEx controller is actually three controllers in one box. One passes high amps to the Armature and the two low amp ones pass amps to the field. Of course, only one of the two is active. Which one depends on if the cart operator is requesting Forward or Reverse.

If you look at a Series drive F/R switch assemble, you will see two microswitches in addition to the high current contacts. The contacts of one switch is closed in both F and R, while the contact in the other only closed in R. The first switch is often incorrectly called or mislabeled "Forward" but it is actually a "Run" switch since its contacts are closed in both F and R. The second switch only sounds the beeper when direction lever is in R, and maybe activates a 1/2 speed reverse function, so it can properly be identified as the reverse switch even though it doesn't actually put cart in reverse, the high current contacts do that.

The DCS controller defaults to Forward and had to be told to go into Reverse.

The first F/R they used in a DCS cart was two microswitches and a diode. With the direction selector in F, the F switch simply told the controller to run, it was already in the F mode. When the direction selector was in the R position, the R switch told the controller to switch to the R Field controller and sound the beeper. The diode was needed to tell the controller to run.

Later, they changed to a F/R that was basically the same microswitch arrangement as the Series F/R has but without the high current contacts. The runs switch closed in both F and R and Reverse switch closed only in R, mechanically eliminating the need of the diode.

The controller in a PDS cart defaults to no direction selected and has to be told which Field controller to use. The F/R switch is simply a SPDT/Center-OFF switch.

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The DCS controller had some design issues and wasn't very durable. Alltrax designed their DCX family of controllers as a plug-n-play replacement.

skipsmith521

If I understand correctly...

The series carts will have a mechanical high amp switch... The one that rotates that passes the amperage.

Both Series and DCS carts have a lever for FR, but the DCS uses micro switches and the series lever is connected to a rotating high amp switch for FR ?

With DCS and PDS, you will not see this high amperage mechanical switch?



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JohnnieB

1. Yes

2. Yes, but there are microswitches on the Series F/R switch assembly also.

3. Yes

scottyb

If the F&R has battery cable connections it is passing high volume battery amperage.

If the F&R has small gauge wire it is passing a low amperage signal to the controller.