Cutsforth Brush Holder User Manual

Cutsforth Brush Holder System

Operation Manual

Cutsforth 7854 12th Avenue South Bloomington, MN 55425 www.cutsforth.com 800.290.6458 fax: [phone]

Part No. CED-1008A

Safety Precautions

Cutsforth Brush Holder Operation Manual

Warning

Introduction

High voltage and rotating parts can cause serious or fatal injury.
Installation, operation, and maintenance of this product must

only be performed by qualied personnel, in accordance with

all applicable manufacturer, OSHA, and local plant safety
regulations and guidelines.

When working with the Cutsforth Brush Holder, it is important to
observe safety precautions. Among the many considerations:

Avoid contact with energized circuits.•

Avoid contact with rotating parts.•

Never install any component that appears to not be •
functioning in a normal manner.

Always ensure proper installation of the brush holder •
assembly.

This manual covers:

introducing Cutsforth Brush Holder components.•

knowing when to change a brush.•

removing the Cutsforth Brush Holder.•

inspecting the holder.•

changing the spring and brush.•

remounting the holder.•

removing and installing the mount.•

Note

This manual does not claim to cover all details or variations in equipment or to
provide for every possible contingency that could be faced during installation,
operation, and maintenance. Should additional information be required, please
contact Cutsforth, Inc.

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Cutsforth Brush Holder Operation Manual

Introducing Cutsforth Brush Holder Components

Handle
(Grip)

Terminal Mount
Rib

Lower Beam

Brush Box

Upper Beam

Catch
Arm

MountHolder

Caution
Do not adjust the 10­32 screw on the top
of the mount. This
fastener is set at the
factory and does not
need to be changed.
Improper adjustment
of this fastener on
older models disables
the over center
locking mechanism.
The latest models
cannot be improperly
adjusted.

Brush Spring Release Fingers

Release Tab

Brush Key

4

Knowing When to Change a Brush

Cutsforth Brush Holder Operation Manual

Caution

Many factors inuence brush wear:

spring pressure•

ring condition•

current density•

atmospheric conditions•

presence of contaminants•

holder condition•

brush grade•

Replace brushes before they become too short. Frequently inspect the brushes to deter­mine if they need to be replaced by checking the wear indicator.

Only replace a small percentage (10%-20%) of brushes at a time if brushes are being

changed “live.” Once installed, allow the new brushes to sufciently wear (seat in at least
50%) to the ring’s prole before replacing more.

Accepted practice is to replace only a small portion of brushes at one time
(this number varies depending on the unit). New brushes only contact the
ring across a very small area. Ensuring that the brush faces are seated at
least 50% before replacing more brushes is typical.

Wear
indicator
on a new
brush

Wear indicator
on a brush that
needs to be
replaced

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Cutsforth Brush Holder Operation Manual

Removing the Holder

Warning

Changing brushes on a unit in operation exposes personnel to dangerous
voltages. Use approved safety gloves while removing the holder.

Caution

Removing multiple holders while the unit is in service can be very

dangerous. The current that was owing through a removed brush is

picked up by the remaining brushes. Removing too many holders at once
can force excessive current through the remaining brushes resulting in
catastrophic failure.

The unlocking motion of the Cutsforth Brush Holder automatically disengages the
terminal so the holder and the brush can safely and easily be removed with one hand.

To remove the holder

While maintaining control of the holder, lift the handle and rotate it to its retracted 1.
position.

Locked or
Engaged
Position

Handle

Retracted
Position

Brush Holder

6

Pull the holder free and away from its mount. Make sure the terminal connection area 2.
on the mount is not excessively worn or pitted.

Terminal
Connection Area

Adapter

Cutsforth Brush Holder Operation Manual

Yoke Bus

.

Mount

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Cutsforth Brush Holder Operation Manual

Online Inspections

It is normally not necessary to remove the brush holder for inspection prior to changing a
worn brush. Watch for the following indicators of problems:

Arching from the trailing edge of the brush (visual).•

Discolored brush leads (visual).•

Brush photographing (imaging) on the ring (visible with strobe).•

The frequency of inspections is unit specic generally ranging from every day to once per

week.

Inspecting the Holder Ofine

To ensure that the holder is in proper working condition, make the following inspections:

Inspect the holder for any signs of wear or damage as well as any excessive build up •
of dirt or foreign material.

Check for any cracking or breakage of components or welds.•

Ensure the brush catch is holding the brush in the brush box when the holder is disen-•
gaged from its mount.

Conrm the “snap in” pressure when installing or removing the holder is relatively •

equal to the other holders.

After the brush has been removed, inspect the sides of the brush for any signs of re-•
strictions such as scrapes or drag marks.

Inspect the inside of the brush box for obstructions such as box deformity, burrs, or •
carbon deposits. Clean the box using denatured alcohol. Remove carbon deposits us­ing a plastic or wood object—avoid using sharp objects or abrasive cleaners as these
could damage the interior of the brush box.

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Cutsforth Brush Holder Operation Manual

Replacing the Spring and Brush

After the holder has been removed from the rigging, the spring and brush can be safely
removed with the use of the Brush Key.

To replace the spring and brush

1. Pull the brush terminal free from the terminal mount rib prior to using
the Brush Key.

Brush Terminal

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Cutsforth Brush Holder Operation Manual

2.

Orient the Brush Key to the correct position in reference to the brush holder (see
illustrations A and B). Slide the Brush Key into the lower beam of the brush holder

(see illustration C). Press down onto a at surface until the Brush Key is fully

engaged (see illustrations D.)

A.

Insert the Brush Key with this Orientation

B.

Do NOT Insert the Brush Key with this Orientation

10

C.

Cutsforth Brush Holder Operation Manual

Slide the Brush Key into the Lower Beam of the brush holder.

Lower Beam

.

.

Flat Surface

D.

.

Press down onto a Flat Surface until the Brush Key snaps into the brush holder.

Flat Surface

.

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Cutsforth Brush Holder Operation Manual

3.

When the Brush Key is fully engaged into the brush holder the old brush will
become free to slide out when holder is pulled away (see illustrations A
and B).

A.

Old Brush

.

12

B.

Old Brush

.

Cutsforth Brush Holder Operation Manual

4.

To remove the old brush spring, press in on the release tab of the Brush Key and pull

it out of the brush holder. The brush spring release ngers will grab the brush spring

as the Brush Key is pulled out of the brush holder. Remove the old brush spring and
discard. (See illustration below)

Cutaway

Old Brush
Spring

.

.

.

.

Release Tab

5. Insert the new brush spring onto the spring rib and push until the spring
hole snaps onto the spring pin. (See illustration below)

Cut Away

.

.

.

Spring Rib

Spring

.

.

.

Spring Pin

Spring Hole

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Cutsforth Brush Holder Operation Manual

6.

To insert the new brush, start by orienting the brush with the terminal ears
pointing down (see illustration A). Then, insert the brush into the holder until
the terminal ears pass the brush spring (see illustration B). Next, rotate the
brush so the terminal ears are pointing up (see illustration C). Then, insert
the brush the rest of the way into the holder until approximately 1/8” is stick­ing out of the brush box (see illustration D).

A.

Brush Spring

.

New Brush

.

.

B.

Terminal Ears Pointing Down

Terminal Clear of Brush Spring

14

C.

Cutsforth Brush Holder Operation Manual

Terminal Ears Pointing Up

D.

Approximately
1/8”

New Brush Fully Engaged

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Cutsforth Brush Holder Operation Manual

7.

Insert the brush terminal onto the terminal mount rib.

Terminal
Mount Rib

Brush Terminal

Cutaway

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Cutsforth Brush Holder Operation Manual

8.

To prevent brush binding, lead damage, and interference with the handle, position
the brush shunts as shown in the following illustrations.

Brush Shunts Formed
Straight Up So They Will
Not Catch on the Box

Handle

Caution: Do not position the brush shunts
as shown or the shunts will restrict free
movement of the brush (hang up).

Brush Shunts
Spread as Shown

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Cutsforth Brush Holder Operation Manual

Returning the Holder to Service

After a new spring and brush are installed, the holder is ready to be returned to service.

To remount the holder

Align the holder with the grooves on the sides of the mount and slide the holder 1.
into the mount.

Holder

Mount

Grooves

Rotate and lock the handle into place while applying light pressure toward the ring. 2.
Once the holder is fully engaged into position, check the brush holder to verify that
it is installed correctly as described on page 19 and that the brush leads are properly
formed as described on page 17.

Yoke
Bus

18

Ring

A.

Incorrectly Mounting the Brush Holder

Cutsforth Brush Holder Operation Manual

I - Misaligned
Insertion

II - Disengaged
Terminal

III - Brush Holder not
Fully Engaged.

B.

Correctly Mounting the Brush Holder

I - Correctly Aligned
Insertion

II - Properly Engaged
Terminal and Holder.

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Cutsforth Brush Holder Operation Manual

Removing and Installing the Holder Mounts

When it is necessary to reinstall the mounts, the following procedures should be fol­lowed.

Warning:

To remove the holder mounts

Before working on the mounts, de-energize and lock-out all power sources to
the generator, exciter, and accessory devices. Electric shock and death may
occur.

Using a 5/32-inch allen wrench, remove the 1/4-28 button head cap screws and 1.
NL6 Nordlock washers.

20

Remove the holder mount.2.

To install the holder mounts

Slide the height setter onto the holder mount until the guide boss is bottomed out in 1.
the guide slot.

Cutsforth Brush Holder Operation Manual

Height Setter

Holder Mount

Guide Boss

Guide Slot

Bottom of Slot

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Cutsforth Brush Holder Operation Manual

Making sure the mount is on the correct side of the adapter, place the holder mount 2.
against one of the adapters on the yoke buss, and position so that the height setter
is resting against the ring so that both ribs are contacting the ring. The adapter
may need to be properly adjusted. To maximize ring coverage, use the alternate
mounting positions on the adapters as needed.

Height Setter with
Mount

Mount Side of
Adapter

Using a 5/32-inch allen wrench, fasten the 1/4-28 button head cap screws and NL6 3.
Nordlock washers to 130 inch-pounds of torque.

Ribs

22

Pull the trigger back to the disengaged position and remove the height setter from 4.
the holder mount.

Cutsforth Brush Holder Operation Manual

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