555.042 MGS-8

Function and operating principle of the 555.042 brush

In service, the brush-holder spring maintains contact pressure between the block and the rotating surface. The brush must move freely in the holder without binding, and the flexible conductor must not restrict its travel. Incorrect dimensions, an unsuitable grade, inadequate pressure or a damaged lead can cause arcing, local overheating, unstable current transfer and accelerated wear.

Selection by appearance alone is not sufficient. A correct order checks the complete drawing number, material grade, carbon-block dimensions, number and position of leads, terminal form, working-face orientation and holder configuration. A visually similar brush of another execution may not satisfy the electrical or mechanical requirements of the applicable unit.

Verified variants, dimensions and applications

Confirmed application variants: applicable unit PT-70TS-2S, grade MGS-8, carbon block 5 × 5 × 16 mm, 1 pc per group, 2 groups in the unit.

The former catalog page associated this position with these searchable unit references: PT-70TS. They are retained for search continuity and old-link verification, while the armature drawing 555.042 is the primary Part Number.

When technical catalogs list several units, grades or dimensions under one drawing, they are presented as confirmed variants inside this single product card. This avoids competing URLs for the same primary Part Number. The required execution must still be confirmed from the maintained unit, removed sample or approved maintenance documentation before supply.

Inspection before installation

Incoming inspection should cover the carbon block, contact face, edges, flexible conductors, lead attachment points and metal terminals. Cracks, deep chips, loose connections, signs of overheating or defects that prevent free holder movement are unacceptable. Dimensions should be measured on the carbon block and should not include lead length unless the drawing defines another method.

After installation, commutator condition, spring pressure, contact-face bedding and allowable wear must be assessed under the maintenance procedure for the applicable unit. Reliable universal values for current density, contact voltage drop, spring force and wear limit across every 555.042 variant were not found in open sources.

Storage, handling and order verification

Before installation, carbon brushes should be kept in dry closed packaging and protected from dust, moisture, oil and accidental mechanical impact. Carbon material is comparatively brittle, so the brush should not be dropped, clamped by its flexible lead or stored under heavy parts. The contact face and terminal should not be ground or treated with aggressive cleaners unless the applicable maintenance procedure requires it, because uncontrolled rework may alter geometry, surface condition or electrical connection quality. Packaging identification should be retained until incoming inspection is complete.

For order verification, a useful inquiry includes a photo of the removed brush beside a measuring tool, a separate view of the terminal and leads, and the designation of the unit and brush holder. Width, thickness and length are measured on the carbon block; flexible-lead length and metal hardware are recorded separately. A worn sample must not be treated as the nominal length. Where one drawing has several listed executions, state the required grade, quantity, brushes per group and known unit modification to reduce the risk of supplying a visually similar but incorrect brush.

Ordering the 555.042 carbon brush

An inquiry should state 555.042, the required grade, dimensions, applicable unit and quantity. The minimum order is 50 pieces. This product is offered in New condition on a pre-order basis with a six-month warranty. Documentation and the exact delivery configuration are confirmed during quotation. More positions are available in the Aviamisto Carbon Brushes category.

Related aviation carbon brushes

Other drawing-based positions available for comparison include 555.043 MGS-8, 555.044 MGS-7i, 555.046 MGS-7, 555.048 MGS-7. These are related products in the same catalog group, not confirmed interchangeable parts. Any replacement must be verified against the armature drawing, material grade, dimensions, lead arrangement and the maintenance documentation for the applicable unit.