{"product_id":"castair-automatic-alternator-relay-230v-mounted-alt230m","title":"Castair Automatic Alternator Relay 230V Mounted - ALT230M","description":"\u003cp\u003eThe \u003cstrong\u003eCastair ALT230M\u003c\/strong\u003e is the mounted-panel version of the 230-volt two-compressor alternator relay. It performs the same function as the ALT230 — automatically alternating the lead\/lag designation between two compressors to equalize running hours — but it ships with the relay already installed in a panel enclosure. Wire to the terminals, mount it to the wall, and the installation is done. No enclosure fabrication, no guesswork about component spacing or mounting hardware.\u003c\/p\u003e\n\n\u003cp\u003eThe M in ALT230M stands for mounted. That distinction matters for how you plan the installation. If you are dropping this relay into an existing control cabinet or custom panel, order the ALT230. If you want a finished, self-contained assembly ready for permanent wall installation, the ALT230M is the correct unit. Both control two compressors on 230V service. Both do the same job. The difference is the enclosure.\u003c\/p\u003e\n\n\u003ch2\u003eWhy Lead\/Lag Control Matters for Two-Compressor Systems\u003c\/h2\u003e\n\n\u003cp\u003eEvery two-compressor system eventually develops the same problem without an alternator relay: one machine does most of the work and wears out early, while the second sits mostly idle. The idle machine ages without exercise, its oil degrades between uses, and when the worn primary finally fails, the backup is not in the condition you expected. The ALT230M prevents this by automatically rotating which compressor is the lead unit each cycle, so hours accumulate evenly across both machines.\u003c\/p\u003e\n\n\u003cp\u003eBeyond maintenance, there are three operating reasons shops specify alternator relays:\u003c\/p\u003e\n\u003cul\u003e\n  \u003cli\u003e\n\u003cstrong\u003eDuty Cycle Compliance:\u003c\/strong\u003e Reciprocating compressors have rated maximum duty cycles — typically expressed as minutes of run time per hour. Running one compressor continuously in a high-demand shop exceeds those ratings and voids the warranty. With the ALT230M cycling both units, each compressor gets recovery time between run cycles, staying inside manufacturer-specified duty cycle limits.\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eRedundancy That Actually Works:\u003c\/strong\u003e Having a second compressor is only useful as backup if that compressor is maintained, exercised regularly, and ready to carry load. The ALT230M keeps the second unit active so when the primary needs service, the shop does not discover the backup has been sitting cold for six months.\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003ePredictable Maintenance Scheduling:\u003c\/strong\u003e When both compressors run equal hours, they need service at the same intervals. One oil change schedule. One filter schedule. One belt inspection schedule. Shops tracking two compressors with unequal hours are always guessing which one needs service and when.\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003ch2\u003eWhy the Mounted Version (ALT230M) vs. the Relay-Only (ALT230)\u003c\/h2\u003e\n\n\u003cp\u003eThe ALT230 and ALT230M perform identically. The choice is about your installation setup:\u003c\/p\u003e\n\u003cul\u003e\n  \u003cli\u003e\n\u003cstrong\u003eChoose ALT230M if:\u003c\/strong\u003e You want a complete, self-contained assembly. The enclosure is done, the relay is mounted, and you wire to labeled terminals. Cleaner installation, less field work, and the relay is protected from the shop environment by the enclosure.\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eChoose ALT230 if:\u003c\/strong\u003e You are installing the relay inside an existing control cabinet, junction box, or custom panel assembly. You supply the enclosure and do the mounting. Lower price, more flexibility on placement and panel layout.\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eIn either case:\u003c\/strong\u003e Have a licensed electrician perform the installation. Compressor control wiring involves line voltage and must be done correctly.\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003ch2\u003eFeatures\u003c\/h2\u003e\n\u003cul\u003e\n  \u003cli\u003e\n\u003cstrong\u003ePre-Mounted Panel Assembly:\u003c\/strong\u003e Relay arrives installed in enclosure — no separate panel fabrication required. Mount to the wall, wire to terminals, done.\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003e230V Rated:\u003c\/strong\u003e Correct for 230V single-phase or 230V three-phase compressor systems. Verify your compressor motor nameplates and panel voltage before ordering.\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eAutomatic Lead\/Lag Alternation:\u003c\/strong\u003e Switches which compressor runs as lead unit each cycle without manual intervention. Hours distribute evenly across both machines automatically.\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eLag Compressor Start:\u003c\/strong\u003e Brings the second unit online automatically when demand exceeds the lead compressor's capacity. Both run until pressure recovers, then lag shuts down first.\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eEnclosed Format:\u003c\/strong\u003e Panel enclosure protects relay from shop dust, moisture, and incidental contact — appropriate for permanent installation in a compressor room or mechanical space.\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eCompatible with Castair Control Accessories:\u003c\/strong\u003e Works with Castair hour meters (HRM75, HRM50), time delays (TD100), and low oil controls (6304, 6304B) for a complete duplex compressor control system.\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eCastair Manufacturing:\u003c\/strong\u003e Built by Cast Air in Minnesota, a manufacturer focused on duplex and industrial compressor controls and systems.\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003ch2\u003eWhat's in the Box\u003c\/h2\u003e\n\u003cul\u003e\n  \u003cli\u003eCastair ALT230M automatic alternator relay, pre-mounted in panel enclosure\u003c\/li\u003e\n  \u003cli\u003eManufacturer documentation and wiring diagram\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003cp\u003eInstallation by a licensed electrician is recommended. The ALT230M is a line-voltage control component for compressor systems.\u003c\/p\u003e\n\n\u003ch2\u003eAvailable Configurations — Full Matrix\u003c\/h2\u003e\n\n\u003cp\u003eCastair offers four alternator relay configurations to match your voltage and installation preference:\u003c\/p\u003e\n\n\u003ctable\u003e\n  \u003cthead\u003e\n    \u003ctr\u003e\n      \u003cth\u003eModel\u003c\/th\u003e\n      \u003cth\u003eVoltage\u003c\/th\u003e\n      \u003cth\u003eFormat\u003c\/th\u003e\n      \u003cth\u003ePrice\u003c\/th\u003e\n      \u003cth\u003eBest For\u003c\/th\u003e\n    \u003c\/tr\u003e\n  \u003c\/thead\u003e\n  \u003ctbody\u003e\n    \u003ctr\u003e\n      \u003ctd\u003e\u003cstrong\u003eALT230\u003c\/strong\u003e\u003c\/td\u003e\n      \u003ctd\u003e230V\u003c\/td\u003e\n      \u003ctd\u003eRelay only — you supply enclosure\u003c\/td\u003e\n      \u003ctd\u003e$398.86\u003c\/td\u003e\n      \u003ctd\u003eInstalling into an existing panel or custom control cabinet on 230V service\u003c\/td\u003e\n    \u003c\/tr\u003e\n    \u003ctr\u003e\n      \u003ctd\u003e\n\u003cstrong\u003eALT230M\u003c\/strong\u003e (this unit)\u003c\/td\u003e\n      \u003ctd\u003e230V\u003c\/td\u003e\n      \u003ctd\u003eRelay pre-mounted in panel enclosure\u003c\/td\u003e\n      \u003ctd\u003eCall for pricing\u003c\/td\u003e\n      \u003ctd\u003eClean permanent wall-mount installation on 230V service — no enclosure fabrication\u003c\/td\u003e\n    \u003c\/tr\u003e\n    \u003ctr\u003e\n      \u003ctd\u003e\u003cstrong\u003eALT460\u003c\/strong\u003e\u003c\/td\u003e\n      \u003ctd\u003e460V\u003c\/td\u003e\n      \u003ctd\u003eRelay only — you supply enclosure\u003c\/td\u003e\n      \u003ctd\u003e$398.86\u003c\/td\u003e\n      \u003ctd\u003e460V three-phase systems, installing into existing panel\u003c\/td\u003e\n    \u003c\/tr\u003e\n    \u003ctr\u003e\n      \u003ctd\u003e\u003cstrong\u003eALT460M\u003c\/strong\u003e\u003c\/td\u003e\n      \u003ctd\u003e460V\u003c\/td\u003e\n      \u003ctd\u003eRelay pre-mounted in panel enclosure\u003c\/td\u003e\n      \u003ctd\u003eCall for pricing\u003c\/td\u003e\n      \u003ctd\u003e460V three-phase systems, clean permanent wall-mount installation\u003c\/td\u003e\n    \u003c\/tr\u003e\n  \u003c\/tbody\u003e\n\u003c\/table\u003e\n\n\u003cp\u003eThe voltage choice is determined by your compressor motor voltage rating and your panel service. The format choice depends on whether you are integrating the relay into an existing panel (ALT230) or want a standalone mounted assembly (ALT230M). Call 866-217-0063 to confirm the right unit for your setup before ordering.\u003c\/p\u003e\n\n\u003ch2\u003eWhen Does a Shop Need This vs. Stepping Up or Down\u003c\/h2\u003e\n\n\u003ch3\u003eThe ALT230M is the right choice if:\u003c\/h3\u003e\n\u003cul\u003e\n  \u003cli\u003eYou are running two compressors on 230V service and want a finished panel assembly rather than a bare relay\u003c\/li\u003e\n  \u003cli\u003eYour installation environment requires enclosed components — dusty compressor rooms, areas with moisture, or anywhere exposed relay components are not appropriate\u003c\/li\u003e\n  \u003cli\u003eYou want a professional, permanent-looking installation without building a custom enclosure\u003c\/li\u003e\n  \u003cli\u003eYou are replacing a failed alternator relay and want a clean drop-in replacement that does not require panel modification\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003ch3\u003eThe ALT230 (relay-only) is better if:\u003c\/h3\u003e\n\u003cul\u003e\n  \u003cli\u003eYou have an existing control cabinet or panel where you are integrating this relay alongside other components\u003c\/li\u003e\n  \u003cli\u003eYour electrician prefers to supply and mount the enclosure to match existing panel hardware on site\u003c\/li\u003e\n  \u003cli\u003eYou want to minimize the purchase cost and handle enclosure yourself\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003ch3\u003eYou need the 460V version if:\u003c\/h3\u003e\n\u003cul\u003e\n  \u003cli\u003eYour compressor motors are rated for 460V three-phase — confirm on the motor nameplate\u003c\/li\u003e\n  \u003cli\u003eInstalling a 230V relay on a 460V circuit is a wiring error that will damage the relay and potentially the compressor. Verify voltage before ordering.\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003ch2\u003eTechnical Specifications\u003c\/h2\u003e\n\u003cul\u003e\n  \u003cli\u003e\n\u003cstrong\u003eModel:\u003c\/strong\u003e ALT230M\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003ePart Number:\u003c\/strong\u003e ALT230M\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eManufacturer:\u003c\/strong\u003e Cast Air (Castair), Minnesota\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eVoltage:\u003c\/strong\u003e 230 Volt\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eApplication:\u003c\/strong\u003e Two-compressor automatic alternation (lead\/lag control)\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eFormat:\u003c\/strong\u003e Relay pre-mounted in panel enclosure\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eCompatible Accessories:\u003c\/strong\u003e HRM75 (hour meter 24-277V), HRM50 (hour meter for gas engines), TD100 (time delay 18-240V, 1-1023 seconds), 6304 (low oil control), 6304B (float switch for low oil)\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003ePrice:\u003c\/strong\u003e Call for current pricing and availability\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eDimensions\/Weight:\u003c\/strong\u003e Contact us to confirm shipping dimensions\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003ch2\u003eWhy Buy From Air Compressor Factory Direct?\u003c\/h2\u003e\n\u003cp\u003eAir Compressor Factory Direct has specialized in compressed air systems and components since 2016. We stock the full Castair control accessory line and understand how these components fit together in a real duplex compressor installation. We can help you choose between the ALT230 and ALT230M, confirm your voltage requirement, and make sure the unit you order matches your actual installation before it ships.\u003c\/p\u003e\n\u003cul\u003e\n  \u003cli\u003e\n\u003cstrong\u003eFree Shipping:\u003c\/strong\u003e On qualifying orders — confirm at checkout or by calling us\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eFree Technical Support:\u003c\/strong\u003e Call 866-217-0063 with installation questions before or after your purchase\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eFull Manufacturer Warranty:\u003c\/strong\u003e All Castair parts covered under manufacturer warranty — we handle warranty issues directly\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eHonest Guidance:\u003c\/strong\u003e If the ALT230M is not the right unit for your installation, we will tell you that before the order ships\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eSpecialist Focus:\u003c\/strong\u003e Compressed air systems and components are what we do. Castair controls are a core part of our inventory and we know the product line.\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003cp\u003e\u003cstrong\u003eCall 866-217-0063 for quick answers and help!\u003c\/strong\u003e\u003c\/p\u003e","brand":"Cast Air","offers":[{"title":"Default Title","offer_id":53342513823957,"sku":"ALT230M","price":1160.14,"currency_code":"USD","in_stock":true}],"url":"https:\/\/aircompressorfactorydirect.com\/products\/castair-automatic-alternator-relay-230v-mounted-alt230m","provider":"Air Compressor Factory Direct","version":"1.0","type":"link"}