Razorfield Ripper

An Equipment doesn't become tapped when the permanent it's attached to becomes tapped. For example, if you attack with a creature that is equipped with Razorfield Ripper, then use reconfigure to unattach Razorfield Ripper after combat, Razorfield Ripper will be untapped and could be used to block during your opponent's turn.

Energy counters are a kind of counter that a player may have. They're not associated with any specific permanents.

An Equipment creature with reconfigure can be attached to creatures by effects other than its reconfigure ability, such as the activated ability of Brass Squire.

Reconfigure represents two activated abilities. Reconfigure [cost] means "[Cost]: Attach this permanent to another target creature you control. Activate only as a sorcery," and "[Cost]: Unattach this permanent. Activate only if this permanent is attached to a creature and only as a sorcery."

The value of X is calculated only once, as Razorfield Ripper's triggered ability resolves.

Some spells and abilities that give you {E} may require targets. If each target chosen is an illegal target as that spell or ability tries to resolve, it won't resolve. You won't get any {E}.

If an Equipment with reconfigure somehow loses its abilities while it is attached, the effect causing it to not be a creature continues to apply until it becomes unattached.

Similarly, if an Equipment is tapped, its reconfigure abilities may still be activated and it may still become attached to creatures. Becoming attached doesn't untap it. In most cases, an attached Equipment being tapped won't affect gameplay, but it will be relevant if it becomes unattached again before it untaps.

As soon as an Equipment creature with reconfigure stops being a creature, any Equipment and Auras with enchant creature abilities become unattached. Auras that can enchant an Equipment that isn't a creature remain attached to it.

Some triggered abilities that state that you "may pay" a certain amount of {E} describe an effect that happens "If you do." In that case, no player may take actions to try to stop the ability's effect after you make your choice. If the payment is followed by the phrase "When you do," then you'll choose any targets for that reflexive triggered ability and put it on the stack before players can take actions.

If a permanent with reconfigure is somehow still a creature after it becomes attached (perhaps due to an effect like that of March of the Machines), it immediately becomes unattached from the equipped creature.

Although it causes an Equipment to become attached to a creature, reconfigure is not an "equip ability" for the purpose of cards like Fighter Class and Leonin Shikari.

{E} is the energy symbol. It represents one energy counter.

An Equipment creature can never become attached to itself. If an effect tries to do this, nothing happens.

If an effect says you get one or more {E}, you get that many energy counters. To pay one or more {E}, you lose that many energy counters. You can't pay more energy counters than you have. Any effects that interact with counters a player gets, has, or loses can interact with energy counters.

If a spell or ability with one or more targets states that you "may pay" some amount of {E}, and each permanent that it targets has become an illegal target, the spell or ability won't resolve. You can't pay any {E} even if you want to.