Description
Key Technical Specifications
| Parameter | Specification |
|---|---|
| Manufacturer | MTL / Eaton MTL |
| Model | 8724-CA-PS |
| Product Type | IS Module Power Supply Carrier |
| System Family | MTL8000 |
| Supported Power Supply | 8920-PS-DC |
| Carrier Capacity | One 8920-PS-DC module |
| Addressing | 32-slot and 64-slot nodes |
| Railbus Connectors | Male input / female output |
| Mounting | DIN rail or flat panel |
| DIN Rail Types | 7.5 × 35 mm, 15 × 35 mm EN 50022; G-section EN 50035 |
| Dimensions | 93 × 168 × 35 mm |
| Weight | Approx. 195 g |
| Carrier Material | Modified poly-phenylene oxide |
| PCB Material | Epoxy resin woven-glass laminate |
| Operating Temperature | -40°C to +70°C |
| Storage Temperature | -40°C to +85°C |
| Relative Humidity | 5–95% RH, non-condensing |
| Hazardous-Area Application | Class I, Div. 2 Groups A–D T4 / Zone 2 IIC T4 |
The manufacturer’s carrier documentation gives the 93 × 168 × 35 mm dimensions, approximately 195 g weight, and the -40°C to +70°C operating range. It also specifies the 32/64-slot Railbus capability.
Application Scenarios & Pain Points
A damaged carrier can be mistaken for a failed power supply. In practice, the distinction matters: replacing the 8920-PS-DC will not correct a cracked PCB, damaged Railbus connector, or mechanically compromised carrier.
Typical Applications
- MTL8000 Power Distribution: The 8724-CA-PS provides the dedicated mounting location for the 8920-PS-DC within an MTL8000 node.
- Intrinsically Safe I/O Systems: The carrier is part of an architecture intended to support MTL8000 I/O modules with intrinsically safe field wiring. Eaton documentation confirms that the 8920-PS-DC mounts on the 8724-CA-PS.
- DIN-Rail Control Cabinets: The carrier can be installed on standard DIN rail or secured directly to a panel, which is useful when replacing older cabinet assemblies without changing the mechanical layout.
- Legacy MTL8000 Maintenance: This part is especially relevant when maintaining an existing node where the 8920-PS-DC and original carrier arrangement are still in service.
Field Case:
When an MTL8000 node loses power, check the carrier before condemning the 8920-PS-DC. Look closely at the Railbus connectors and PCB around the power-supply interface. A loose or heat-damaged contact can produce intermittent symptoms that disappear when the cabinet door or module is moved.
8724-CA-PS
Related Products
- MTL 8920-PS-DC — The actual DC power-supply module installed on the 8724-CA-PS. It accepts nominal 24 VDC and provides 12 VDC for I/O modules; it is not mechanically or functionally equivalent to the carrier.
- MTL 8725-CA-RB — Railbus isolator carrier with power-fail monitoring. It serves a different position in the architecture and should not be substituted for the 8724-CA-PS.
- MTL 8723-CA-RB — Railbus isolator carrier. It handles Railbus isolation rather than providing the dedicated 8920-PS-DC mounting location.
- MTL 8717-CA-PS — Carrier intended specifically for the 8910-PS-DC supply. The carrier therefore differs from 8724-CA-PS in the power-supply module it accepts.
- MTL 8910-PS-DC — An DC power-supply family component associated with other carrier arrangements. Verify the carrier part number before substitution.
- MTL 8922-RB-IS — Railbus signal isolator used in architectures. It is associated with Railbus isolation rather than the system power-supply carrier.
- MTL 8000 IS Module Carriers — The wider carrier family includes 4-module and 8-module carriers such as 8720-CA-04, 8727-CA-08, and 8729-CA-08. These provide I/O-module mounting rather than the dedicated power-supply position.
The Engineer’s Guide: Field Pitfalls to Avoid
⚠️ Do Not Order 8724-CA-PS When You Actually Need 8920-PS-DC
The names are easily confused. 8724-CA-PS is the carrier; 8920-PS-DC is the power supply. Eaton explicitly states that the 8920-PS-DC mounts on its own 8724-CA-PS carrier.
How to avoid it: Put both part numbers on the maintenance BOM when replacing a complete power-supply assembly:
Carrier: 8724-CA-PS
Power Supply: 8920-PS-DC
⚠️ Inspect the Railbus Connectors
The carrier is part of the node’s Railbus interconnection. Mechanical damage, contamination, or poor seating can interrupt communication or power distribution.
How to avoid it: During replacement, inspect male/female Railbus contacts for bent pins, oxidation, foreign material, and mechanical looseness. Do not force a mating connector.
⚠️ Do Not Assume All Carriers Are Interchangeable
The 8724-CA-PS is specifically designed to accommodate one 8920-PS-DC. Other carrier numbers perform different functions.
How to avoid it: Match the carrier part number to the power-supply model and node architecture before installation. A similar-looking carrier is not adequate evidence of compatibility.
Frequently Asked Questions (FAQ)
What is MTL 8724-CA-PS?
The 8724-CA-PS is an IS module power supply carrier in the family. Its primary job is to mount and electrically interface one 8920-PS-DC power-supply module with the system.
It is therefore a carrier/interface assembly, not the source of the 12 VDC output.
What power supply fits the 8724-CA-PS?
The specified power supply is 8920-PS-DC. Eaton documentation states that the 8920-PS-DC mounts on the 8724-CA-PS and supplies I/O modules.
The 8920-PS-DC itself accepts a nominal 24 VDC input and provides a 12 VDC output.
Is 8724-CA-PS a power supply?
No. This is the most important procurement distinction.
8724-CA-PS = carrier
8920-PS-DC = power supply
A supplier listing that calls 8724-CA-PS a standalone power-supply module is technically misleading. The manufacturer’s own documentation identifies it as the IS module power supply carrier.
Can 8724-CA-PS be DIN-rail mounted?
Yes. It supports DIN-rail or flat-panel mounting. The documented DIN-rail options include 7.5 × 35 mm and 15 × 35 mm EN 50022 rails, as well as G-section EN 50035 rail.
What are the dimensions of 8724-CA-PS?
The published dimensions are approximately 93 mm wide × 168 mm deep × 35 mm high, with a weight of approximately 195 g.
These dimensions are useful when checking an old cabinet before replacing a mechanically damaged carrier.
What should I check when buying a used 8724-CA-PS?
Request photographs of the actual carrier, particularly:
- Complete 8724-CA-PS marking
- PCB and connector condition
- Railbus male/female connectors
- 8920-PS-DC mounting interface
- DIN-rail clips
- Panel mounting points
- Evidence of corrosion or overheating
- Functional continuity/connection testing
- Warranty terms
A carrier does not have the same functional test profile as an electronic I/O module. Mechanical and electrical-interface inspection is therefore especially important.
Is 8724-CA-PS suitable for hazardous-area applications?
The manufacturer documentation specifies use associated with Class I, Division 2 Groups A–D T4 and Zone 2, IIC T4 hazardous locations, with an operating ambient range of -40°C to +70°C.
