{"product_id":"cnc-jr28s-thermal-overload-relay","title":"Thermal Overload Relay | Motor Overload Protection Relay for Contactors (JR28s \/ LR2)","description":"\u003cdiv style=\"font-family:-apple-system,BlinkMacSystemFont,'Segoe UI',Roboto,Arial,sans-serif;font-size:15px;line-height:1.7;color:#222;max-width:820px;margin:0 auto;\"\u003e\n\n\u003cdiv style=\"background:#fff5f5;border-left:4px solid #d42027;padding:16px 18px;margin:0 0 24px;border-radius:4px;\"\u003e\n\u003cp style=\"font-size:15px;line-height:1.7;margin:0;\"\u003e\u003cstrong\u003eQuick answer:\u003c\/strong\u003e The CNC JR28S is a \u003cstrong\u003ethermal overload relay\u003c\/strong\u003e that protects a motor from burning out. It clips onto a matching contactor, senses the motor current, and trips if the motor draws too much for too long — from a stalled rotor, a jammed load, a lost phase or a failing winding. Adjustable across the full range from \u003cstrong\u003e0.1 A to 630 A\u003c\/strong\u003e, trip class 10A, built to IEC 60947-4-1. Price on request.\u003c\/p\u003e\n\u003c\/div\u003e\n\n\u003cp style=\"font-size:15px;line-height:1.7;margin:0 0 14px;\"\u003eA motor that draws even 15–20% over its rated current will overheat and cook its winding insulation given enough time — but not fast enough to blow a fuse. A \u003cstrong\u003ethermal overload relay\u003c\/strong\u003e is what catches that slow overload: it heats up in step with the motor and trips the control circuit before the motor is damaged.\u003c\/p\u003e\n\n\u003ch2 style=\"font-size:22px;font-weight:700;margin-top:34px;margin-bottom:12px;color:#111;\"\u003eWhat the JR28S does\u003c\/h2\u003e\n\n\u003cp style=\"font-size:15px;line-height:1.7;margin:0 0 14px;\"\u003eThe JR28S carries the motor current through internal bimetallic strips that bend as they heat. On a sustained overload they trip an auxiliary contact that drops out the contactor, disconnecting the motor. It includes \u003cstrong\u003ephase-loss (differential) protection\u003c\/strong\u003e, \u003cstrong\u003eambient-temperature compensation\u003c\/strong\u003e, and a selectable \u003cstrong\u003emanual or automatic reset\u003c\/strong\u003e. It mounts directly onto its matching contactor (or on a separate base plate) to form a complete starter.\u003c\/p\u003e\n\n\u003ch2 style=\"font-size:22px;font-weight:700;margin-top:34px;margin-bottom:12px;color:#111;\"\u003eFull current range (0.1–630 A)\u003c\/h2\u003e\n\n\u003cp style=\"font-size:15px;line-height:1.7;margin:0 0 14px;\"\u003eEach frame size covers a set of overlapping adjustable current ranges — set the dial to your motor's full-load current:\u003c\/p\u003e\n\n\u003ctable style=\"width:100%;border-collapse:collapse;margin:18px 0;font-size:14px;\"\u003e\n\u003ctr\u003e\n\u003cth style=\"border:1px solid #d0d0d0;background:#f0f0f0;padding:8px;text-align:left;font-weight:700;\"\u003eFrame\u003c\/th\u003e\n\u003cth style=\"border:1px solid #d0d0d0;background:#f0f0f0;padding:8px;text-align:left;font-weight:700;\"\u003eCurrent-adjustment ranges (A)\u003c\/th\u003e\n\u003cth style=\"border:1px solid #d0d0d0;background:#f0f0f0;padding:8px;text-align:left;font-weight:700;\"\u003eMatching contactor\u003c\/th\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd style=\"border:1px solid #d0d0d0;padding:8px;\"\u003eJR28s-25\u003c\/td\u003e\n\u003ctd style=\"border:1px solid #d0d0d0;padding:8px;\"\u003e0.1–0.16 · 0.16–0.25 · 0.25–0.4 · 0.4–0.63 · 0.63–1 · 1–1.6 · 1.25–2 · 1.6–2.5 · 2.5–4 · 4–6 · 5.5–8 · 7–10 · 9–13 · 12–18 · 17–25 · 23–32\u003c\/td\u003e\n\u003ctd style=\"border:1px solid #d0d0d0;padding:8px;\"\u003eCJX2 09–25\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr style=\"background:#f9f9f9;\"\u003e\n\u003ctd style=\"border:1px solid #d0d0d0;padding:8px;\"\u003eJR28s-36\u003c\/td\u003e\n\u003ctd style=\"border:1px solid #d0d0d0;padding:8px;\"\u003e23–32 · 28–36\u003c\/td\u003e\n\u003ctd style=\"border:1px solid #d0d0d0;padding:8px;\"\u003eCJX2 32\/38\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd style=\"border:1px solid #d0d0d0;padding:8px;\"\u003eJR28s-93\u003c\/td\u003e\n\u003ctd style=\"border:1px solid #d0d0d0;padding:8px;\"\u003e23–32 · 30–40 · 37–50 · 48–65 · 55–70 · 63–80 · 80–93\u003c\/td\u003e\n\u003ctd style=\"border:1px solid #d0d0d0;padding:8px;\"\u003eCJX2 40–95\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr style=\"background:#f9f9f9;\"\u003e\n\u003ctd style=\"border:1px solid #d0d0d0;padding:8px;\"\u003eJR28s-150\u003c\/td\u003e\n\u003ctd style=\"border:1px solid #d0d0d0;padding:8px;\"\u003e80–104 · 95–120 · 110–150\u003c\/td\u003e\n\u003ctd style=\"border:1px solid #d0d0d0;padding:8px;\"\u003eCJX2F 115\/150\/170\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd style=\"border:1px solid #d0d0d0;padding:8px;\"\u003eJR28s-200\u003c\/td\u003e\n\u003ctd style=\"border:1px solid #d0d0d0;padding:8px;\"\u003e80–125 · 100–160 · 125–200\u003c\/td\u003e\n\u003ctd style=\"border:1px solid #d0d0d0;padding:8px;\"\u003eCJX2F 115–225\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr style=\"background:#f9f9f9;\"\u003e\n\u003ctd style=\"border:1px solid #d0d0d0;padding:8px;\"\u003eJR28s-630\u003c\/td\u003e\n\u003ctd style=\"border:1px solid #d0d0d0;padding:8px;\"\u003e160–250 · 200–315 · 250–400 · 315–500 · 400–630\u003c\/td\u003e\n\u003ctd style=\"border:1px solid #d0d0d0;padding:8px;\"\u003eCJX2F 185–630\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003c\/table\u003e\n\n\u003ch2 style=\"font-size:22px;font-weight:700;margin-top:34px;margin-bottom:12px;color:#111;\"\u003eKey specifications\u003c\/h2\u003e\n\n\u003ctable style=\"width:100%;border-collapse:collapse;margin:18px 0;font-size:15px;\"\u003e\n\u003ctr\u003e\n\u003cth style=\"border:1px solid #d0d0d0;background:#f0f0f0;padding:10px;text-align:left;font-weight:700;\"\u003eFeature\u003c\/th\u003e\n\u003cth style=\"border:1px solid #d0d0d0;background:#f0f0f0;padding:10px;text-align:left;font-weight:700;\"\u003eDetail\u003c\/th\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd style=\"border:1px solid #d0d0d0;padding:10px;\"\u003eSetting current (full range)\u003c\/td\u003e\n\u003ctd style=\"border:1px solid #d0d0d0;padding:10px;\"\u003e0.1–630 A\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr style=\"background:#f9f9f9;\"\u003e\n\u003ctd style=\"border:1px solid #d0d0d0;padding:10px;\"\u003eRated operating voltage\u003c\/td\u003e\n\u003ctd style=\"border:1px solid #d0d0d0;padding:10px;\"\u003e380 V\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd style=\"border:1px solid #d0d0d0;padding:10px;\"\u003eRated insulation voltage Ui\u003c\/td\u003e\n\u003ctd style=\"border:1px solid #d0d0d0;padding:10px;\"\u003e660 V\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr style=\"background:#f9f9f9;\"\u003e\n\u003ctd style=\"border:1px solid #d0d0d0;padding:10px;\"\u003eImpulse withstand Uimp\u003c\/td\u003e\n\u003ctd style=\"border:1px solid #d0d0d0;padding:10px;\"\u003e6 kV\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd style=\"border:1px solid #d0d0d0;padding:10px;\"\u003eTrip class\u003c\/td\u003e\n\u003ctd style=\"border:1px solid #d0d0d0;padding:10px;\"\u003eClass 10A\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr style=\"background:#f9f9f9;\"\u003e\n\u003ctd style=\"border:1px solid #d0d0d0;padding:10px;\"\u003eReset\u003c\/td\u003e\n\u003ctd style=\"border:1px solid #d0d0d0;padding:10px;\"\u003eManual (≤2 min) or automatic (≤8 min), selectable\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd style=\"border:1px solid #d0d0d0;padding:10px;\"\u003ePhase-loss protection\u003c\/td\u003e\n\u003ctd style=\"border:1px solid #d0d0d0;padding:10px;\"\u003eYes (differential)\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr style=\"background:#f9f9f9;\"\u003e\n\u003ctd style=\"border:1px solid #d0d0d0;padding:10px;\"\u003eTemperature compensation\u003c\/td\u003e\n\u003ctd style=\"border:1px solid #d0d0d0;padding:10px;\"\u003eYes\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd style=\"border:1px solid #d0d0d0;padding:10px;\"\u003eAuxiliary contacts\u003c\/td\u003e\n\u003ctd style=\"border:1px solid #d0d0d0;padding:10px;\"\u003e1NO + 1NC\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr style=\"background:#f9f9f9;\"\u003e\n\u003ctd style=\"border:1px solid #d0d0d0;padding:10px;\"\u003eStandard\u003c\/td\u003e\n\u003ctd style=\"border:1px solid #d0d0d0;padding:10px;\"\u003eIEC 60947-4-1\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd style=\"border:1px solid #d0d0d0;padding:10px;\"\u003eAmbient \/ altitude\u003c\/td\u003e\n\u003ctd style=\"border:1px solid #d0d0d0;padding:10px;\"\u003e≤ +40 °C, ≤2000 m\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003c\/table\u003e\n\n\u003ch2 style=\"font-size:22px;font-weight:700;margin-top:34px;margin-bottom:12px;color:#111;\"\u003eModel code and mounting\u003c\/h2\u003e\n\n\u003cp style=\"font-size:15px;line-height:1.7;margin:0 0 14px;\"\u003eThe code reads \u003cstrong\u003eJR28s-[frame] \/ [mounting]\u003c\/strong\u003e, where the frame is the size (25, 36, 93, 150, 200, 630) and the mounting code is \u003cstrong\u003eZ\u003c\/strong\u003e = stack-mount (piggyback) directly onto the contactor, or \u003cstrong\u003eF\u003c\/strong\u003e = separate mount on a base plate. The JR28S is the CNC equivalent of the widely used LR2 \/ LRD relay footprint.\u003c\/p\u003e\n\n\u003ch2 style=\"font-size:22px;font-weight:700;margin-top:34px;margin-bottom:12px;color:#111;\"\u003eWhat the JR28S does \u003cem\u003enot\u003c\/em\u003e do\u003c\/h2\u003e\n\n\u003cp style=\"font-size:15px;line-height:1.7;margin:0 0 14px;\"\u003eA thermal overload relay protects against \u003cstrong\u003eoverload only\u003c\/strong\u003e — the slow, sustained over-current. It does not break short-circuit faults; that needs an upstream circuit breaker or fuse in the starter. It also needs a contactor to actually switch the motor. For a single device that combines switching, overload and short-circuit protection, see the \u003ca href=\"\/products\/cnc-yckb7-control-protective-switching-cps-motor-starter\" style=\"color:#d42027;text-decoration:underline;\"\u003eCNC YCKB7 integrated motor starter\u003c\/a\u003e.\u003c\/p\u003e\n\n\u003ch2 style=\"font-size:22px;font-weight:700;margin-top:34px;margin-bottom:12px;color:#111;\"\u003eDownloads\u003c\/h2\u003e\n\u003cul style=\"margin:0 0 16px;padding-left:22px;\"\u003e\n\u003cli style=\"font-size:15px;line-height:1.7;margin-bottom:8px;\"\u003e\u003ca href=\"https:\/\/www.cncele.com\/uploads\/JR28-JR28s-series-Instructions-22.12.9.pdf\" style=\"color:#d42027;text-decoration:underline;\"\u003eJR28S instruction manual — IEC 60947-4-1 (PDF)\u003c\/a\u003e\u003c\/li\u003e\n\u003cli style=\"font-size:15px;line-height:1.7;margin-bottom:8px;\"\u003e\u003ca href=\"https:\/\/www.cncele.com\/uploads\/JR28s-%E6%A0%B7%E6%9C%AC-23.11.18.pdf\" style=\"color:#d42027;text-decoration:underline;\"\u003eJR28S catalogue (PDF)\u003c\/a\u003e\u003c\/li\u003e\n\u003cli style=\"font-size:15px;line-height:1.7;margin-bottom:8px;\"\u003e\u003ca href=\"https:\/\/www.cncele.com\/uploads\/2201-JR28JR28SJR28NLR9-CE-certification-GTS1.pdf\" style=\"color:#d42027;text-decoration:underline;\"\u003eCE certificate (PDF)\u003c\/a\u003e\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003ch2 style=\"font-size:22px;font-weight:700;margin-top:34px;margin-bottom:12px;color:#111;\"\u003eFrequently asked questions\u003c\/h2\u003e\n\n\u003ch3 style=\"font-size:17px;font-weight:700;margin-top:22px;margin-bottom:6px;color:#111;\"\u003eWhat is a thermal overload relay?\u003c\/h3\u003e\n\u003cp style=\"font-size:15px;line-height:1.7;margin:0 0 14px;\"\u003eIt is a motor-protection device that trips when a motor draws too much current for too long. It heats up in step with the motor and, on a sustained overload, opens a contact that drops the contactor and disconnects the motor before it burns out.\u003c\/p\u003e\n\n\u003ch3 style=\"font-size:17px;font-weight:700;margin-top:22px;margin-bottom:6px;color:#111;\"\u003eHow do I set the relay current?\u003c\/h3\u003e\n\u003cp style=\"font-size:15px;line-height:1.7;margin:0 0 14px;\"\u003eSet the adjustment dial to the motor's full-load current from its nameplate, within the relay's range. Pick the frame and range that brackets that current — for example a 15 A motor sits in the 12–18 A range on a JR28s-25.\u003c\/p\u003e\n\n\u003ch3 style=\"font-size:17px;font-weight:700;margin-top:22px;margin-bottom:6px;color:#111;\"\u003eHow does it mount?\u003c\/h3\u003e\n\u003cp style=\"font-size:15px;line-height:1.7;margin:0 0 14px;\"\u003eIt stack-mounts directly onto its matching contactor (code Z) for a compact starter, or on a separate base plate (code F). The matching-contactor column in the range table shows which contactor each frame fits.\u003c\/p\u003e\n\n\u003ch3 style=\"font-size:17px;font-weight:700;margin-top:22px;margin-bottom:6px;color:#111;\"\u003eDoes it protect against a lost phase?\u003c\/h3\u003e\n\u003cp style=\"font-size:15px;line-height:1.7;margin:0 0 14px;\"\u003eYes — built-in differential phase-loss protection trips the relay if one phase is lost, which would otherwise quickly overheat a three-phase motor.\u003c\/p\u003e\n\n\u003ch3 style=\"font-size:17px;font-weight:700;margin-top:22px;margin-bottom:6px;color:#111;\"\u003eManual or automatic reset — which should I use?\u003c\/h3\u003e\n\u003cp style=\"font-size:15px;line-height:1.7;margin:0 0 14px;\"\u003eManual reset is safer for most machinery, so a trip is investigated before restart. Automatic reset suits unattended equipment that should restart itself once it cools. The JR28S lets you select either.\u003c\/p\u003e\n\n\u003ch3 style=\"font-size:17px;font-weight:700;margin-top:22px;margin-bottom:6px;color:#111;\"\u003eDoes it also break short circuits?\u003c\/h3\u003e\n\u003cp style=\"font-size:15px;line-height:1.7;margin:0 0 14px;\"\u003eNo. It handles overload only. Pair it with an upstream breaker or fuse for short-circuit protection, or use a CPS like the YCKB7 that includes both.\u003c\/p\u003e\n\n\u003cdiv style=\"background:#f7f7f9;border-left:4px solid #d42027;padding:16px 18px;margin:28px 0;border-radius:4px;\"\u003e\n\u003cp style=\"font-size:15px;line-height:1.7;margin:0;\"\u003eWant switching and protection in one device? See the \u003ca href=\"\/products\/cnc-yckb7-control-protective-switching-cps-motor-starter\" style=\"color:#d42027;text-decoration:underline;\"\u003eCNC YCKB7 CPS\u003c\/a\u003e, or add a \u003ca href=\"\/products\/cnc-ycqr7-motor-soft-starter\" style=\"color:#d42027;text-decoration:underline;\"\u003eCNC YCQR7 soft starter\u003c\/a\u003e for gentle starts. Browse the full \u003ca href=\"\/collections\/industrial-products\" style=\"color:#d42027;text-decoration:underline;\"\u003eCNC industrial products\u003c\/a\u003e range.\u003c\/p\u003e\n\u003c\/div\u003e\n\n\u003cdiv style=\"background:#fff5f5;border:1px solid #f0c9c9;padding:16px 18px;margin:24px 0 0;border-radius:4px;\"\u003e\n\u003cp style=\"font-size:15px;line-height:1.7;margin:0;\"\u003eSend us your motor full-load current and contactor and we'll confirm the exact JR28S range and mounting. \u003cstrong\u003eCNC Electric\u003c\/strong\u003e is the authorised CNC distributor in Pakistan — \u003ca href=\"https:\/\/wa.me\/923261111376\" style=\"color:#d42027;text-decoration:underline;\"\u003emessage us on WhatsApp\u003c\/a\u003e for a price and quote.\u003c\/p\u003e\n\u003c\/div\u003e\n\n\u003c\/div\u003e\n","brand":"CNC","offers":[{"title":"0.1–0.16 A","offer_id":45153523859522,"sku":"JR28s-25-016","price":0.0,"currency_code":"PKR","in_stock":true},{"title":"1–1.6 A","offer_id":45153523892290,"sku":"JR28s-25-1D6","price":0.0,"currency_code":"PKR","in_stock":true},{"title":"4–6 A","offer_id":45153523925058,"sku":"JR28s-25-006","price":0.0,"currency_code":"PKR","in_stock":true},{"title":"5.5–8 A","offer_id":45153523957826,"sku":"JR28s-25-008","price":0.0,"currency_code":"PKR","in_stock":true},{"title":"9–13 A","offer_id":45153523990594,"sku":"JR28s-25-013","price":0.0,"currency_code":"PKR","in_stock":true},{"title":"17–25 A","offer_id":45153524023362,"sku":"JR28s-25-025","price":0.0,"currency_code":"PKR","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0605\/2059\/5522\/files\/JR28S-over-load-relay1-600x600.jpg?v=1788507693","url":"https:\/\/www.cncelectric.pk\/products\/cnc-jr28s-thermal-overload-relay","provider":"CNC Electric Pakistan","version":"1.0","type":"link"}