Slipring Brush Block Replacement

Prerequisites

Table 2. Tools and test equipment
Item	Quantity	Effectivity	Part number	Manufacturer
Flat-blade screwdriver	1	-	-	-
Flat blade hex drive bit for torque driver	1	-	-	-
4mm,5 mm, 10mm Hex Keys	1	-	-	-
FE torque wrench kit	1	-	5122203 or equivilent

Table 4. Safety

ELECTROCUTION HAZARD
High Voltages present.
Use proper lockout/tagout procedures before replacing components. See safety menu of Service Document gui for appropriate procedures.

Follow ALL required safety and PPE procedures customary for your organization when working on this product.

Overview

This procedure defines the necessary steps to replace a brush block assembly.

Move table to its lowest elevation.
Remove gantry covers as required.

Refer to Parts Replacement > Gantry > Enclosure > (Cover Removal Procedure).

Electrocution hazard
High Voltage present.
Use proper lockout/tagout procedures before replacing components. See safety menu of Service Document gui for appropriate procedures.

Perform Lockout Tagout for system power (A1 disconnect) prior to replacing this component.
Remove Rear Gantry cover support bracket.
Remove Slipring covers.
Remove four (4) M6 cap screws that secure brush block assembly to gantry.
Carefully remove brush block.

note: New brush tips are supplied with the brush block. Do not reuse old brushes.
Inspect each brush tip for wear. Each tip will have a triangle stamped on one side. When the brush wears to the point of the triangle the brush must be replaced.

Brush Contamination Possible. Do not touch brushes with your fingers. The skin oils will contaminate the brush and reduce usable life and potentially create future failures.

Remove individual brushes from the block as necessary by unscrewing brush cap and extracting brush.
note:
Since brushes are spring-loaded to ensure constant contact with the slipring during operation, the springs will relax when the block is removed, causing brushes to bound outwards.

If brush is to be reused make sure you install it in the same orientation as removed. The brush was seated/conditioned in that position.
notice

Brush Tip Damage Possible. Brush tips are extremely brittle. Do not apply sideways force as they will break. Any brush that has been damaged in this fashion must be replaced.
Clean the slip ring prior to installing the new brush block and brushes. Use the PM Procedure for cleaning the slip ring.
Carefully install brush block by exerting even pressure perpendicular to the ring surface.
Secure brush block with the four (4) 6 mm cap screws. Do not tighten yet.
Carefully push brush block against the position adjustment set screws in the mounting bracket.
Reassemble gantry.

Hardware Reset using console gantry reset (Hardwire).
Acquire 10 scouts: (120kV/40mA., 1000mm table movement)
Acquire 100 axials: (120kV/80mA., 0.5 sec. Scan)
Acquire 1 helical: (120kV/40mA., 30 sec. Scan)
Acquire 10 axial scans: (120kV/400mA., 4 sec. Scan)
Verify NO increase in LSCOM errors.
To check LSCOM Statistics:

Select Log Viewing, System Browser, Run Time Statistics, RCOM/SCOM Statistics.