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Technical Tips & FAQs
Converting KTA3-25 to KT4 Motor Controllers
Question: My panel uses a KTA3-25 motor controller. What is the replacement for this device?
Answer: KT4 Manual Motor Controllers are a direct replacement for KTA3-25 controllers with only a few exceptions.
In 2001 Sprecher + Schuh introduced the KT7 series of Motor Controllers. The KT7 is a superior design to the then popular KTA3 series of manual motor controllers. KT7 Series offers high KAIC ratings and is UL approved as a Type E motor control and protection device. The older KTA3 design gradually started to phase out in 2003 with more and more limited availability and UL changes affecting ratings. In 2005 it was discontinued completely. However, some users were still in need of the manual motor starter design the KTA3 represented.
To accommodate the KTA3 users, the KT4 Manual Motor Starters were introduced in 2004. The KT4 matched the KTA3 design almost perfectly except for some UL ratings. The old KTA3-25 was good up to 25 Amps, but UL changes limited the KT4 ratings to a maximum of 16 amps. The KT4 was designed to fit the same foot print, enclosures and accessories of the KTA3-25. Older panel designs can be outfitted with KT4 as a direct replacement for KTA3-25. Distributors with old KTA3 accessories and enclosures can use them with the KT4 controllers and vice versa (see cross reference chart below).
Almost all KTA3 products convert to a comparable KT4 catalog number. There is one important instance where KT4 is not a direct replacement for KTA3-25. The KTA3 series offered a current limiter accessory (KLT3-65) that, when placed in front of the KTA3, increased the fault current (KA) to the controller. Used in multi-motor starter panels, the current limiter was attached in series with compact bus bar. If a legacy control panel utilizes the KLT3-65, Sprecher & Schuh does not offer any direct replacement for that current limiter. The entire panel downstream from the KLT3-65 is in jeopardy and a new design using KT7 series controllers should be considered. Contact Technical Support immediately for design assistance.
| Motor Controllers & Auxiliaries | Catalog Number | |
|---|---|---|
| KTA3 Series | KT4 Series | |
| 0.1 - 0.16 A | KTA3-25-0.16A | KT4-C2A-A16 |
| 0.16 - 0.25 A | KTA3-25-0.25A | KT4-C2A-A25 |
| 0.25 - 0.4 A | KTA3-25-0.4A | KT4-C2A-A40 |
| 0.4 - 0.63 A | KTA3-25-0.63A | KT4-C2A-A63 |
| 0.63 - 1 A | KTA3-25-1A | KT4-C2A-B10 |
| 1 - 1.6 A | KTA3-25-1.6A | KT4-C2A-B16 |
| 1.6 - 2.5 A | KTA3-25-2.5A | KT4-C2A-B25 |
| 2.5 - 4 | KTA3-25-4A | KT4-C2A-B40 |
| 4 - 6.3 A | KTA3-25-6.3A | KT4-C2A-B63 |
| 6.3 - 10 A | KTA3-25-10A | KT4-C2A-C10 |
| 10 - 16 A | KTA3-25-16A | KT4-C2A-C16 |
| 16 - 20 A | KTA3-25-20A | KTA7-25S-20A |
| 20 - 25 A | KTA3-25-25A | KTA7-25S-25A |
| Auxiliary Contact Block (NO) | KT3-25-PE1-10 | KT4-C-AEA10 |
| Auxiliary Contact Block (NO) PA Type | KT3-25-PE2-10 | KT4-C-AEA210 |
| Auxiliary Contact Block (NC) | KT3-25-PE1-01 | KT4-C-AEA01 |
| Auxiliary Contact Block (NC) PA Type | KT3-25-PE2-01 | KT4-C-AEA201 |
| Auxiliary Contact Block (NOEM) | KT3-25-PE-L10 | no cross |
| Two pole Auxiliary Contact Block (NO/NC) | KT3-25-PA-11 | KT4-C-ASA11 |
| Two pole Auxiliary Contact Block -(NO/NO) | KT3-25-PA-20 | KT4-C-ASA20 |
| Two pole Auxiliary Contact Block -(NC/NC) | KT3-25-PA-02 | KT4-C-ASA02 |
| Trip Indicator (NO) Internal Add On | KT3-25-PF-10 | No cross |
| Trip Indicator (NC) Internal Add On | KT3-25-PF-01 | No cross |
| Undervoltage Release Module | KT3-25-UA-* | KT4-C-UX* |
| Shunt Release Module | KT3-25-AA-* | KT4-C-SX* |
| Current Limiter | KTL3-65-N | No Cross |
| Adaptor Plate | KT3-25-AS | KT4-C-N12 |
| Locking Fixture | KTA3-25-DSC | KT4-C-M3 |
| Connecting Module | KT3-NW23 | KT4-C-PNC23 |
| Enclosure Surface Mount General Purpose (IP41) | KT3-25-KA | KT4-C-EA41 |
| Enclosure Surface Mount Watertight (IP55) | KT3-25-KAZ | KT4-C-EA55 |
| Enclosure Flush Mount General Purpose (IP41) | ~ | KT4-C-EE41 |
| Enclosure Flush Mount Watertight (IP55) | ~ | KT4-C-EE55 |
| Enclosure Locking Fixture | KT3-25-DS | KT4-c-M3E |
| Enclosure Membrane | KT3-25-DM | KT4-c-N18 |
| Compact Bus Bar 45mm - 2 controllers | ?KT3-25-DB-45-2 | KT4-C-W452 |
| Compact Bus Bar 45mm - 3 controllers | KT3-25-DB-45-3 | KT4-C-W453 |
| Compact Bus Bar 45mm - 4 controllers | KT3-25-DB-45-4 | KT4-C-W454 |
| Compact Bus Bar 45mm - 5 controllers | KT3-25-DB-45-5 | KT4-C-W455 |
| Compact Bus Bar 54mm - 2 controllers | KT3-25-DB-54-2 | KT4-C-W542 |
| Compact Bus Bar 54mm - 3 controllers | KT3-25-DB-54-3 | KT4-C-W543 |
| Compact Bus Bar 54mm - 4 controllers | KT3-25-DB-54-4 | KT4-C-W544 |
| Compact Bus Bar 54mm - 5 controllers | KT3-25-DB-54-5 | KT4-C-W545 |
| Supply Block | KT3-25-A2 | no cross |
| Supply Block | KT3-25-A3 | KT4-C-WT |
| Blank Space Bus Bar Cover | KT3-25-DBA | KT4-C-WS |
Categories: Motor Circuit Controllers
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