Choose an Albright SW or SU contactor by its circuit function and complete part specification. SW and SU identify families; they do not define one current rating, coil duty or contact arrangement for every member.
Main contactors compared
| Type | Contact function | Interrupted thermal rating | Uninterrupted thermal rating |
|---|---|---|---|
| SW80 | Normally open, single pole, single throw | 100 A | 125 A |
| SU80 | Normally open, single pole, single throw | 150 A | 200 A |
| SU280 | Normally open, single pole, single throw | 250 A | 350 A |
These figures come from Albright's individual product tables. They are type-level thermal ratings under the manufacturer's conditions. They do not replace the switching-capacity, voltage, load and duty checks for the ordered variant.
SW does not always mean a simple on/off switch
The SW family also includes different contact arrangements. SW182 is a motor-reversing type, as are DC88 and DC182. Do not substitute a main contactor for a reversing assembly merely because the current or coil voltage matches.
Coil voltage and contact voltage are separate
The coil is the control input. Main contacts carry the load power. Check both circuits independently, including any suppression components and polarity markings. An AC-operated coil with a rectifier does not by itself establish an AC main-contact switching rating.
Interrupted load, uninterrupted load and coil duty
Use the manufacturer's terminology consistently. A load-carrying thermal rating is different from a stated capacity to make or break current. Coil duty concerns how long the coil may remain energised; it is a separate check from contact duty. Continuous-coil and intermittent-coil variants must be selected for their actual operating sequence.
A higher rating is not an interchangeability statement
Albright describes SU80 as an uprated version of SW80. That does not establish that every SU80 variant can replace every SW80 variant. Verify dimensions, brackets, terminals, coil characteristics, contact voltage and the controller's requirements.
Frequently asked questions
Which is better, SW or SU?
The correct choice is the variant that meets the circuit, load, duty and installation specification. A family label alone cannot answer that question.
Is fault breaking capacity a normal operating rating?
No. A fault rating applies to stated test conditions. Do not use it as an ordinary motor-current or continuous-current rating.
Where should I begin?
Browse Albright contactors, then follow the guides for winches, thrusters or industrial DC equipment.
Manufacturer references
Technical sources checked 11 October 2026. Verify the current datasheet for the complete ordered part number.
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